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Kuszewska K, Woloszczuk A, Woyciechowski M. Reproductive Cessation and Post-Reproductive Lifespan in Honeybee Workers. BIOLOGY 2024; 13:287. [PMID: 38785769 PMCID: PMC11117506 DOI: 10.3390/biology13050287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024]
Abstract
The post-reproductive lifespan is an evolutionary enigma because the cessation of reproduction in animals seems contrary to the maximization of Darwinian fitness. Several theories aim to explain the evolution of menopause, one of which suggests that females of a certain age receive more fitness benefits via indirect selection (kin selection) than they would directly from continuing reproduction. Post-reproductive lifespans are not very common in nature but have been described in humans, nonhuman primates, a few species of toothed whales, guppies, and in some insect societies consisting of clonal colony members, such as aphid and ant societies. Here, we provide evidence that menopause also exists in honeybee societies. Our study shows that workers with a short life expectancy (older and/or injured workers) invest fewer resources and less time in their own reproduction than workers with a long life expectancy (younger and/or uninjured workers), even if their colony is hopelessly queenless. These results are consistent with the kin selection explanation for the evolution of menopause and help us understand the net effects of relatedness and social cooperation in animals.
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Affiliation(s)
- Karolina Kuszewska
- Department of Zoology and Animal Welfare, Faculty of Animal Science, University of Agriculture in Krakow, Al. Mickiewicza 21, 31-120 Krakow, Poland
| | - Anna Woloszczuk
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Krakow, Poland
| | - Michal Woyciechowski
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Krakow, Poland
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2
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Blagosklonny MV. Are menopause, aging and prostate cancer diseases? Aging (Albany NY) 2023; 15:298-307. [PMID: 36707068 PMCID: PMC9925691 DOI: 10.18632/aging.204499] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 01/16/2023] [Indexed: 01/28/2023]
Abstract
There is no doubt that prostate cancer is a disease. Then, according to hyperfunction theory, menopause is also a disease. Like all age-related diseases, it is a natural process, but is also purely harmful, aimless and unintended by nature. But exactly because these diseases (menopause, prostate enlargement, obesity, atherosclerosis, hypertension, diabetes, presbyopia and thousands of others) are partially quasi-programmed, they can be delayed by slowing aging. Is aging a disease? Aging is a quasi-programmed disease that is partially treatable by rapamycin. On the other hand, aging is an abstraction, a sum of all quasi-programmed diseases and processes. In analogy, the zoo consists of animals and does not exist without animals, but the zoo is not an animal.
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3
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Martins R, de Sousa B, Rodrigues V. The geography of the age at menopause in central Portugal since the early twentieth century. Sci Rep 2022; 12:22020. [PMID: 36539449 PMCID: PMC9768149 DOI: 10.1038/s41598-022-25475-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
This work aims at studying the spatio-temporal evolution of the age at menopause in central Portugal since the early twentieth century. We analyzed [Formula: see text] women that had already reached the menopause within a free breast cancer screening program between 1990 and 2018 and born in the period 1910-1960. One of the concerns was about early or late menopause thus we considered percentile regression to build the respective percentile curves inside the package GAMLSS in R. In order to capture the correlation at the regional level, a spatial random-effect was considered. The obtained clustered spatial effects were analyzed to assess geographical differences among the percentiles of the age at menopause by year of birth. An increasing trend in the median age at menopause and regional differences for all the considered percentiles were found. From 47.1 years in 1910 to 49.59 years in 1960 (about 2.49 years in 5 decades). Early and premature menopause (below percentile 5%) occur in the interior north (north-eastern). Late menopause (above percentile 95%) occur predominantly in the central-north and central-south areas.
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Affiliation(s)
- Rui Martins
- Departamento de Estatística e Investigação Operacional, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal.
- Centro de Estatística e Aplicações da Universidade de Lisboa (CEAUL), Lisboa, Portugal.
| | - Bruno de Sousa
- Faculty of Psychology and Education Sciences (FPCE), Center for Research in Neuropsychology and Cognitive and Behavioral Intervention (CINEICC), University of Coimbra, Coimbra, Portugal
| | - Vítor Rodrigues
- Faculty of Medicine, University of Coimbra, Rua Larga, 3004-504, Coimbra, Portugal
- Liga Portuguesa Contra o Cancro, Núcleo Regional do Centro, Rua Dr. Antonio José de Almeida, 329 - piso 2 - Sala 56, 3000-045, Coimbra, Portugal
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4
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Davison R, Gurven M. The importance of elders: Extending Hamilton's force of selection to include intergenerational transfers. Proc Natl Acad Sci U S A 2022; 119:e2200073119. [PMID: 35867741 PMCID: PMC9282300 DOI: 10.1073/pnas.2200073119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 04/27/2022] [Indexed: 11/18/2022] Open
Abstract
In classical evolutionary models, the force of natural selection diminishes with age toward zero by last reproduction. However, intergenerational resource transfers and other late-life contributions in social species may select for postreproductive longevity. We present a formal framework for estimating indirect fitness contributions via production transfers in a skills-intensive foraging niche, reflecting kinship and cooperation among group members. Among contemporary human hunter-gatherers and horticulturalists, indirect fitness contributions from transfers exceed direct reproductive contributions from before menopause until ages when surpluses end, around the modal age of adult death (∼70 y). Under reasonable assumptions, these benefits are the equivalent to having up to several more offspring after age 50. Despite early independence, minimal production surplus, and a shorter lifespan, chimpanzees could theoretically make indirect contributions if they adopted reliable food-sharing practices. Our results for chimpanzees hypothetically adopting hunter-gatherer subsistence suggest that a skills-intensive foraging ecology with late independence and late peak production could select for human-like life histories via positive feedback between longevity and late-life transfers. In contrast, life history changes preceding subsistence shifts would not favor further life extension or subsistence shifts. Our results formalize the theory that longevity can be favored under socioecological conditions characterized by parental and alloparental care funded through transfers of mid- to late-life production surpluses. We also extend our analysis beyond food transfers to illustrate the potential for indirect fitness contributions from pedagogy, or information transfers. While we focus mostly on humans, our approach is adaptable to any context or species where transfers can affect fitness.
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Affiliation(s)
- Raziel Davison
- Department of Anthropology, University of California, Santa Barbara, CA 93106
- Broom Center for Demography, University of California, Santa Barbara, CA 93106
| | - Michael Gurven
- Department of Anthropology, University of California, Santa Barbara, CA 93106
- Broom Center for Demography, University of California, Santa Barbara, CA 93106
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5
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How evolutionary biology can explain why human and a few marine mammal females are the only ones that are menopausal. J Theor Biol 2022; 543:111123. [DOI: 10.1016/j.jtbi.2022.111123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 03/31/2022] [Accepted: 04/03/2022] [Indexed: 11/21/2022]
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6
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Stark O. Menopause as a regulatory device for matching the demand for children with its supply: A hypothesis. ECONOMICS AND HUMAN BIOLOGY 2021; 42:101001. [PMID: 33965649 DOI: 10.1016/j.ehb.2021.101001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 03/02/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
Drawing on two assumptions: that menopause is an instrument for the efficient regulation of the duration of a biologically expensive state, and that people have children in order to obtain support from them in old age, we set out a new idea that seeks to explain both the occurrence of menopause and its timing. On the basis of the notion that the purpose of having children is to obtain support in old age, we perceive menopause as an upper limit to the fertile state, when a continued ability to give birth to children would not generate the desired support. The conjecture yields specific testable predictions, and can be assessed against the "reproductive conflict" hypothesis. Being supported by one's offspring is a distinctive feature of humans; in this context, we cannot rely on animal studies in evolutionary biology and related fields to help us to ascertain something that is specific to humans.
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Affiliation(s)
- Oded Stark
- University of Bonn, Bonn, Germany; University of Warsaw, Warsaw, Poland.
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7
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Sugianto NA, Newman C, Macdonald DW, Buesching CD. Reproductive and Somatic Senescence in the European Badger (Meles meles): Evidence from Lifetime Sex-Steroid Profiles. ZOOLOGY 2020; 141:125803. [PMID: 32574816 DOI: 10.1016/j.zool.2020.125803] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 05/02/2020] [Accepted: 05/04/2020] [Indexed: 10/24/2022]
Abstract
Among the Carnivora, there is sparse evidence for any substantive fitness benefits of post reproductive lifespan (PRLS, survival after reproductive cessation, RC). Using the European badger (Meles meles) as a model species, we analyzed sex-specific cross-sectional endocrinological and morphological data to investigate: 1) age-dependent reproductive decline in sex-steroid levels versus prime reproductive age; 2) age-dependent declines in somatic condition and reproductive advertisement (from subcaudal scent gland secretion); 3) changes in reproductive success with age due to somatic and endocrinological decline; 4) occurrence of RC, PRLS, and post reproductive representation (PrR) in the population with reference to pre-pubescent hormone levels and evidenced by fewer cub assignments from pedigree. We provide strong evidence for a gradual, not abrupt, decline in sex-steroid levels with age, with both sexes following a concave (down) quadratic trend. For both sexes, the onset of decline in somatic condition commenced at the age of 3 years. In contrast, decline in reproductive hormones started at age ca. 5.5 years in females and 6 years in males, with similar rates of decline thereafter. Subcaudal gland secretion volume also decreased in both sexes, especially after age 5, suggesting less investment in reproductive advertisement. After age 3, fewer (surviving) females were assigned cubs. This coincided with the onset of somatic decline but came earlier than hormonal decline (5.5 years onwards). The decrease in offspring assignments commenced later in males at age 5-6 years; concomitant with onset of testosterone decline at 6 years. This suggests that, contrary to females, in males declining body condition does not preclude reproductive success (no 'restraint') in advance of hormonal senescence ('constraint'). There was evidence of female PRLS, with very old adults living up to 2.59 ± 1.29 years after RC; although in males this evidence was weaker. We discuss the implications of these findings for RC and PRLS in the context of adaptive and non-adaptive hypotheses. There was evidence of over 2 years of Post Reproductive Life Span in both sexes.
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Affiliation(s)
- Nadine Adrianna Sugianto
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Abingdon Road, Tubney House, Tubney, Oxfordshire OX13 5QL, UK
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Abingdon Road, Tubney House, Tubney, Oxfordshire OX13 5QL, UK
| | - David W Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Abingdon Road, Tubney House, Tubney, Oxfordshire OX13 5QL, UK
| | - Christina D Buesching
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Abingdon Road, Tubney House, Tubney, Oxfordshire OX13 5QL, UK.
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8
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Nichols HJ, Arbuckle K, Fullard K, Amos W. Why don’t long-finned pilot whales have a widespread postreproductive lifespan? Insights from genetic data. Behav Ecol 2020. [DOI: 10.1093/beheco/arz211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
In a handful of mammals, females show an extended postreproductive lifespan (PRLS), leading to questions over why they spend a substantial portion of their lifespan nonreproductive. Theoretical and empirical studies suggest that PRLS may evolve when 1) demographic patterns lead to increasing local relatedness as females age, and 2) females come into reproductive competition with their daughters, as these conditions lead to high relative benefits of helping kin versus reproducing in later life. However, evolutionary pathways to PRLS are poorly understood and empirical studies are scarce. Here, we use a dataset of 1522 individuals comprising 22 pods to investigate patterns of reproduction and relatedness in long-finned pilot whales Globicephala melas; a toothed whale without species-wide PRLS. We find a similar relatedness structure to whales with PRLS: pods appear composed of related matrilines, and relatedness of females to their pod increases with age, suggesting that this species could benefit from late-life help. Furthermore, females with a large number of philopatric adult daughters are less likely to reproduce, implying intergenerational reproductive competition between females. This suggests that individuals may display a plastic cessation of reproduction, switching to investing in existing offspring when they come into competition with their daughters. To the best of our knowledge, this is the first time such a relationship has been described in relation to PRLS, and it raises questions about whether this represents a step towards evolving PRLS or is a stable alternative strategy to widespread postreproductive periods.
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Affiliation(s)
- Hazel J Nichols
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
- Department of Animal Behaviour, Bielefeld University, Postfach, Bielefeld, Germany
| | - Kevin Arbuckle
- Department of Biosciences, College of Science, Swansea University, Swansea, UK
- Department of Evolution, Ecology and Behaviour, University of Liverpool, Liverpool, UK
| | - Karen Fullard
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - William Amos
- Department of Zoology, University of Cambridge, Cambridge, UK
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Thomas F, Giraudeau M, Renaud F, Ujvari B, Roche B, Pujol P, Raymond M, Lemaitre JF, Alvergne A. Can postfertile life stages evolve as an anticancer mechanism? PLoS Biol 2019; 17:e3000565. [PMID: 31805037 PMCID: PMC6917346 DOI: 10.1371/journal.pbio.3000565] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/17/2019] [Indexed: 12/14/2022] Open
Abstract
Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecological or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers, nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e.g., hormone-dependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary mismatch between anticancer defenses and cancer risks, the evolution of prolonged life after reproduction could also be a rare, potentially transient, anticancer adaptation in the animal kingdom.
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Affiliation(s)
- Frédéric Thomas
- Centre de Recherches Ecologiques et Evolutives sur le Cancer/Centre de Recherches en Ecologie et Evolution de la Santé, Unité Mixte de Recherches, Institut de Recherches pour le Développement 224-Centre National de la Recherche Scientifique 5290-Université de Montpellier, Montpellier, France
| | - Mathieu Giraudeau
- Centre de Recherches Ecologiques et Evolutives sur le Cancer/Centre de Recherches en Ecologie et Evolution de la Santé, Unité Mixte de Recherches, Institut de Recherches pour le Développement 224-Centre National de la Recherche Scientifique 5290-Université de Montpellier, Montpellier, France
| | - François Renaud
- Centre de Recherches Ecologiques et Evolutives sur le Cancer/Centre de Recherches en Ecologie et Evolution de la Santé, Unité Mixte de Recherches, Institut de Recherches pour le Développement 224-Centre National de la Recherche Scientifique 5290-Université de Montpellier, Montpellier, France
| | - Beata Ujvari
- Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Benjamin Roche
- Centre de Recherches Ecologiques et Evolutives sur le Cancer/Centre de Recherches en Ecologie et Evolution de la Santé, Unité Mixte de Recherches, Institut de Recherches pour le Développement 224-Centre National de la Recherche Scientifique 5290-Université de Montpellier, Montpellier, France
- Unité mixte internationale de Modélisation Mathématique et Informatique des Systèmes Complexes, Unité Mixte de Recherches, Institut de Recherches pour le développement/Sorbonne Université, France
- Departamento de Etología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, México
| | - Pascal Pujol
- Centre de Recherches Ecologiques et Evolutives sur le Cancer/Centre de Recherches en Ecologie et Evolution de la Santé, Unité Mixte de Recherches, Institut de Recherches pour le Développement 224-Centre National de la Recherche Scientifique 5290-Université de Montpellier, Montpellier, France
- CHU Arnaud de Villeneuve, Montpellier, France
| | - Michel Raymond
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Jean-François Lemaitre
- Centre National de la Recherche Scientifique, Unité mixte de recherche 5558, Laboratoire de Biométrie et Biologie Evolutive, Université Lyon 1 Villeurbanne, France
| | - Alexandra Alvergne
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
- Institute of Social and Cultural Anthropology, School of Anthropology and Museum Ethnography, University of Oxford, United Kingdom
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10
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Auld JR. The effects of diet and mating system on reproductive (and post-reproductive) life span in a freshwater snail. Ecol Evol 2018; 8:12260-12270. [PMID: 30598816 PMCID: PMC6303742 DOI: 10.1002/ece3.4689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/09/2018] [Accepted: 10/12/2018] [Indexed: 02/05/2023] Open
Abstract
The length of the reproductive life span, along with the number/frequency/magnitude of reproductive events, quantifies an individual's potential contribution to the next generation. By examining reproductive life span, and distinguishing it from somatic life span, we gain insight into critical aspects of an individual's potential fitness as well as reproductive and somatic senescence. Additionally, differentiating somatic and reproductive life spans can provide insight into the existence of a post-reproductive period and factors that shape its duration. Given the known importance of diet and mating system on resource allocation, I reared individual freshwater snails (Physa acuta) from 22 full-sib families under a 2 × 2 factorial design that crossed mate availability (available [outcrossing] or not [selfing]) and diet (Spirulina or lettuce) and quantified aspects of the entire life history enabling me to distinguish reproductive and somatic life spans, determine the total number of reproductive events, and evaluate how the reproductive rate changes with age. Overall, mated snails experienced shorter reproductive and somatic life spans; a diet of Spirulina also shortened both reproductive and somatic life spans. A post-reproductive period existed in all conditions; its duration was proportional to somatic but not reproductive life span. I evaluate several hypotheses for the existence and duration of the post-reproductive period, including a novel hypothesis that the post-reproductive period may result from an increase in reproductive interval with age. I conclude that the post-reproductive period may be indicative of a randomly timed death occurring as the interval between reproductive events continues to increase. As such, a "post-reproductive" period can be viewed as a by-product of a situation where reproductive senescence outpaces somatic senescence.
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Affiliation(s)
- Josh R. Auld
- Department of BiologyWest Chester UniversityWest ChesterPennsylvania
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11
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Lubinsky M. Evolutionary justifications for human reproductive limitations. J Assist Reprod Genet 2018; 35:2133-2139. [PMID: 30116921 DOI: 10.1007/s10815-018-1285-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/02/2018] [Indexed: 01/27/2023] Open
Abstract
Common human reproductive inefficiencies have multiple etiologies. Going against chance, many effects, such as polycystic ovaries, endometriosis, and folate metabolic issues, have genetic components, while aneuploid losses arise from diverse mitotic and meiotic errors at different stages, some transitory. This can be advantageous, since greater overall survival with fewer offspring can increase reproductive success. Benefits primarily accrue to mothers, who bear most child related costs, and for whom early losses are less costly than late. Different adaptations to different situations reflect human evolutionary history. For early speciation, periodic climate extremes repeatedly reduced resources, favoring limitations while contracted populations helped fix relevant genes. Later, under better conditions, evolving social cooperation could increase fecundity faster than it added resources, further supporting reproductive suppression through mitotic aneuploidy, with very early losses minimizing maternal costs. The grandmother hypothesis suggests benefits in limiting reproduction as maternal age increased pregnancy risks in order to support grandchildren as they arrived, selecting for maternal age-related meiotic aneuploidy. Finally, with variable short-term agricultural shortages, acute reproductive responses arose through chromatin "nutrient sensor"-regulated epigenetic effects that also shifted some lethal effects earlier, reducing both maternal and mutation load costs. Overall, despite suggestions to the contrary, it is likely that human selective pressures have not decreased with civilization, but that many of the costs have been shifted to early reproduction.
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Garay J, Számadó S, Varga Z, Szathmáry E. Caring for parents: an evolutionary rationale. BMC Biol 2018; 16:53. [PMID: 29764437 PMCID: PMC5953408 DOI: 10.1186/s12915-018-0519-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/13/2018] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The evolutionary roots of human moral behavior are a key precondition to understanding human nature. Investigations usually start with a social dilemma and end up with a norm that can provide some insight into the origin of morality. We take the opposite direction by investigating whether the cultural norm that promotes helping parents and which is respected in different variants across cultures and is codified in several religions can spread through Darwinian competition. RESULTS We show with a novel demographic model that the biological rule "During your reproductive period, give some of your resources to your post-fertile parents" will spread even if the cost of support given to post-fertile grandmothers considerably decreases the demographic parameters of fertile parents but radically increases the survival rate of grandchildren. The teaching of vital cultural content is likely to have been critical in making grandparental service valuable. We name this the Fifth Rule, after the Fifth Commandment that codifies such behaviors in Christianity. CONCLUSIONS Selection for such behavior may have produced an innate moral tendency to honor parents even in situations, such as those experienced today, when the quantitative conditions would not necessarily favor the maintenance of this trait.
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Affiliation(s)
- J Garay
- MTA-ELTE Theoretical Biology and Evolutionary Ecology Research Group and Department of Plant Systematics, Ecology and Theoretical Biology, L. Eötvös University, Pázmány P. sétány 1/C, Budapest, H-1117, Hungary
- MTA Centre for Ecological Research, Evolutionary Systems Research Group, Klebelsberg Kuno utca 3, Tihany, 8237, Hungary
| | - S Számadó
- RECENS "Lendület" Research Group, MTA Centre for Social Science, Tóth Kálmán u. 4, Budapest, H-1097, Hungary
- MTA Centre for Ecological Research, Evolutionary Systems Research Group, Klebelsberg Kuno utca 3, Tihany, 8237, Hungary
| | - Z Varga
- Department of Mathematics, Szent István University, Páter K. u. 1, Gödöllő, H-2103, Hungary
| | - E Szathmáry
- Parmenides Center for the Conceptual Foundations of Science, Kirchplatz 1, 82049, Pullach/Munich, Germany.
- MTA Centre for Ecological Research, Evolutionary Systems Research Group, Klebelsberg Kuno utca 3, Tihany, 8237, Hungary.
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Gaillard JM, Lemaître JF. The Williams' legacy: A critical reappraisal of his nine predictions about the evolution of senescence. Evolution 2017; 71:2768-2785. [DOI: 10.1111/evo.13379] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 09/25/2017] [Accepted: 09/30/2017] [Indexed: 12/16/2022]
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14
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The mystery of life beyond menopause. Nat Ecol Evol 2017; 1:1604-1605. [DOI: 10.1038/s41559-017-0356-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Florea M. Aging and immortality in unicellular species. Mech Ageing Dev 2017; 167:5-15. [PMID: 28844968 DOI: 10.1016/j.mad.2017.08.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/21/2017] [Accepted: 08/13/2017] [Indexed: 12/22/2022]
Abstract
It has been historically thought that in conditions that permit growth, most unicellular species do not to age. This was particularly thought to be the case for symmetrically dividing species, as such species lack a clear distinction between the soma and the germline. Despite this, studies of the symmetrically dividing species Escherichia coli and Schizosaccharomyces pombe have recently started to challenge this notion. They indicate that E. coli and S. pombe do age, but only when subjected to environmental stress. If true, this suggests that aging may be widespread among microbial species in general, and that studying aging in microbes may inform other long-standing questions in aging. This review examines the recent evidence for and against replicative aging in symmetrically dividing unicellular organisms, the mechanisms that underlie aging, why aging evolved in these species, and how microbial aging fits into the context of other questions in aging.
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Affiliation(s)
- Michael Florea
- Graduate School of Arts and Sciences, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA.
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16
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Thouzeau V, Raymond M. Emergence and maintenance of menopause in humans: A game theory model. J Theor Biol 2017; 430:229-236. [PMID: 28739172 DOI: 10.1016/j.jtbi.2017.07.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/14/2017] [Accepted: 07/19/2017] [Indexed: 11/27/2022]
Abstract
Menopause, the permanent cessation of ovulation, occurs in women well before the end of their expected life span. Several adaptive hypotheses have been proposed to solve this evolutionary puzzle, each based on a possible fitness benefit derived from an early reproductive senescence, but no consensus has emerged. The construction of a game theory model allowed us to jointly study the main adaptive hypotheses in emergence and maintenance of menopause. Four classical hypotheses on the benefits of menopause were considered (decreased maternal mortality, increased grandmothering, decreased conflict over reproductive resources between older and younger females, and changes in their relatedness) plus a fifth one derived from a possible pleiotropic trade-off. Interestingly, the conditions for the emergence of menopause are more restrictive than those for its maintenance due to the social and familial changes induced by the occurrence of non-reproductive older women.
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Affiliation(s)
- Valentin Thouzeau
- Institute of Evolutionary Sciences, CNRS, IRD, EPHE CC 065, University of Montpellier, Place Eugène Bataillon, 34095 Montpellier cédex 05, France; Eco-Anthropology and Ethnobiology Lab, UMR 7206, 57 rue Cuvier, Museum National d'Histoire Naturelle, 75005 Paris, France.
| | - Michel Raymond
- Institute of Evolutionary Sciences, CNRS, IRD, EPHE CC 065, University of Montpellier, Place Eugène Bataillon, 34095 Montpellier cédex 05, France.
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Lemaître JF, Gaillard JM. Reproductive senescence: new perspectives in the wild. Biol Rev Camb Philos Soc 2017; 92:2182-2199. [PMID: 28374548 DOI: 10.1111/brv.12328] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/23/2017] [Accepted: 03/03/2017] [Indexed: 11/26/2022]
Abstract
According to recent empirical studies, reproductive senescence, the decline in reproductive success with increasing age, seems to be nearly ubiquitous in the wild. However, a clear understanding of the evolutionary causes and consequences of reproductive senescence is still lacking and requires new and integrative approaches. After identifying the sequential and complex nature of female reproductive senescence, we show that the relative contributions of physiological decline and alterations in the efficiency of parental care to reproductive senescence remain unknown and need to be assessed in the light of current evolutionary theories of ageing. We demonstrate that, although reproductive senescence is generally studied only from the female viewpoint, age-specific female reproductive success strongly depends on male-female interactions. Thus, a reduction in male fertilization efficiency with increasing age has detrimental consequences for female fitness. Lastly, we call for investigations of the role of environmental conditions on reproductive senescence, which could provide salient insights into the underlying sex-specific mechanisms of reproductive success. We suggest that embracing such directions should allow building new bridges between reproductive senescence and the study of sperm competition, parental care, mate choice and environmental conditions.
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Affiliation(s)
- Jean-François Lemaître
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, F-69622, Villeurbanne, France
| | - Jean-Michel Gaillard
- Univ Lyon, Université Lyon 1; CNRS, Laboratoire de Biométrie et Biologie Évolutive UMR5558, F-69622, Villeurbanne, France
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Takahashi M, Singh RS, Stone J. A Theory for the Origin of Human Menopause. Front Genet 2017; 7:222. [PMID: 28111590 PMCID: PMC5216033 DOI: 10.3389/fgene.2016.00222] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 12/13/2016] [Indexed: 11/25/2022] Open
Abstract
A complete and compelling evolutionary explanation for the origin of human menopause is wanting. Menopause onset is defined clinically as the final menses, confirmed after 1 year without menstruation. The theory proposed herein explains at multiple levels - ultimately genetic but involving (1) behavioral, (2) life history, and (3) social changes - the origin and evolution of menopause in women. Individuals in Lower Paleolithic human populations were characterized by short lifespans with diminished late-age survival and fertility, similar to contemporary chimpanzees, and thence were subject to three changes. (1) A mating behavior change was established in which only young women reproduced, thereby rendering as effectively neutral female-specific late-onset fertility-diminishing mutations, which accumulated subsequently. (2) A lifespan increase was manifested adaptively, revealing the reproductive senescence phenotype encoded in late-onset fertility-diminishing mutation genotypes, which, heretofore, had been unexpressed in the shorter lifespan. (3) A social interaction change emerged exaptively, when older non-reproductive women exclusively started assisting in rearing grandchildren rather than giving birth to and caring for their own children, ultimately leading to menstrual cycle cessation. The changes associate in a one-to-one manner with existing, non-mutually exclusive hypotheses for the origin of human menopause. Evidence for each hypothesis and its associated change having occurred are reviewed, and the hypotheses are combined in a synthetic theory for the origin of human menopause. The new theory simultaneously addresses the main theoretical problem with each hypothesis and yields predictions for future testing.
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Affiliation(s)
| | - Rama S. Singh
- Department of Biology, Origins Institute, McMaster University, HamiltonON, Canada
| | - John Stone
- Department of Biology, Origins Institute, McMaster University, HamiltonON, Canada
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Abstract
Demography, lacking an overarching theoretical framework of its own, has drawn on theories in many other social sciences to inform its analyses. The aim of this paper is to bring to the demographic community's attention research in the evolutionary sciences on fertility, and to demonstrate that evolutionary theory can be another useful tool in the demographer's toolkit. I first dispel some myths which impede the incorporation of evolutionary theory into demography: I make it clear that evolutionary explanations do not assume that all human behaviour is hardwired and functions to maximize genetic fitness; that they are able to explain variation in human behaviour; and that they are not necessarily alternatives to social science explanations. I then describe the diversity of work on fertility by evolutionary researchers, particularly human evolutionary ecologists and cultural evolutionists, and illustrate the usefulness of the evolutionary approach with examples of its application to age at first birth and the fertility transition.
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Affiliation(s)
- Rebecca Sear
- a London School of Hygiene and Tropical Medicine
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20
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Kowald A, Kirkwood TBL. Can aging be programmed? A critical literature review. Aging Cell 2016; 15:986-998. [PMID: 27534524 PMCID: PMC6398523 DOI: 10.1111/acel.12510] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2016] [Indexed: 02/02/2023] Open
Abstract
The evolution of the aging process has long been a biological riddle, because it is difficult to explain the evolution of a trait that has apparently no benefit to the individual. Over 60 years ago, Medawar realized that the force of natural selection declines with chronological age because of unavoidable environmental risks. This forms the basis of the mainstream view that aging arises as a consequence of a declining selection pressure to maintain the physiological functioning of living beings forever. Over recent years, however, a number of articles have appeared that nevertheless propose the existence of specific aging genes; that is, that the aging process is genetically programmed. If this view were correct, it would have serious implications for experiments to understand and postpone aging. Therefore, we studied in detail various specific proposals why aging should be programmed. We find that not a single one withstands close scrutiny of its assumptions or simulation results. Nonprogrammed aging theories based on the insight of Medawar (as further developed by Hamilton and Charlesworth) are still the best explanation for the evolution of the aging process. We hope that this analysis helps to clarify the problems associated with the idea of programmed aging.
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Affiliation(s)
- Axel Kowald
- Institute of Cell and Molecular Biosciences, and Institute for Ageing; Newcastle University; Campus for Ageing and Vitality Newcastle upon Tyne NE4 5PL UK
| | - Thomas B. L. Kirkwood
- Institute of Cell and Molecular Biosciences, and Institute for Ageing; Newcastle University; Campus for Ageing and Vitality Newcastle upon Tyne NE4 5PL UK
- Center for Healthy Aging; Department of Cellular and Molecular Medicine; University of Copenhagen; Blegdamsvej 3B 2200 Copenhagen Denmark
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Nichols HJ, Zecherle L, Arbuckle K. Patterns of philopatry and longevity contribute to the evolution of post-reproductive lifespan in mammals. Biol Lett 2016; 12:20150992. [PMID: 26888915 PMCID: PMC4780556 DOI: 10.1098/rsbl.2015.0992] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
While menopause has long been known as a characteristic trait of human reproduction, evidence for post-reproductive lifespan (PRLS) has recently been found in other mammals. Adaptive and non-adaptive hypotheses have been proposed to explain the evolution of PRLS, but formal tests of these are rare. We use a phylogenetic approach to evaluate hypotheses for the evolution of PRLS among mammals. In contrast to theoretical models predicting that PRLS may be promoted by male philopatry (which increases relatedness between a female and her group in old age), we find little evidence that male philopatry led to the evolution of a post-reproductive period. However, the proportion of life spent post-reproductive was related to lifespan and patterns of philopatry, suggesting that the duration of PRLS may be impacted by both non-adaptive and adaptive processes. Finally, the proportion of females experiencing PRLS was higher in species with male philopaty and larger groups, in accordance with adaptive models of PRLS. We suggest that the origin of PRLS primarily follows the non-adaptive 'mismatch' scenario, but that patterns of philopatry may subsequently confer adaptive benefits of late-life helping.
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Affiliation(s)
- H J Nichols
- School of Natural Science and Psychology, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - L Zecherle
- School of Natural Science and Psychology, Liverpool John Moores University, Liverpool L3 3AF, UK
| | - K Arbuckle
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
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Subsistence-patterns, gender roles, effective temperature, and the evolutionary timing of a post reproductive life span. Med Hypotheses 2016; 89:48-57. [PMID: 26968909 DOI: 10.1016/j.mehy.2016.01.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/21/2016] [Accepted: 01/29/2016] [Indexed: 11/23/2022]
Abstract
Evolutionary anthropologists explain menopause and the start of a post reproductive lifespan (PRLS), as beneficiary for older women who can now help contribute to their children/grandchildren's wellbeing. This paper presents a new model with the aim to elucidate when, where, and for whom, such benefits may have arisen. In foraging societies, women contribute nutrients to their social groups/family units to a greater degree as overall effective temperatures (ETs) rise. Where the ET is favorable for women's contributions (ETs between 15 and 20), selection does lengthen the PRLS of women because women contribute sufficiently to enhance their own inclusive fitness. Paleo-environment records suggest that the climate necessary to encourage an increase PRLS occurred shortly after the younger dryad in emerging subtropical settings. Subsistence patterns and gender roles may have played a role in the evolution of PRLS in human females.
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23
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English S, Browning LE, Raihani NJ. Developmental plasticity and social specialization in cooperative societies. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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24
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The evolution of prolonged life after reproduction. Trends Ecol Evol 2015; 30:407-16. [DOI: 10.1016/j.tree.2015.04.011] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/17/2015] [Accepted: 04/21/2015] [Indexed: 11/24/2022]
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Snopkowski K, Moya C, Sear R. A test of the intergenerational conflict model in Indonesia shows no evidence of earlier menopause in female-dispersing groups. Proc Biol Sci 2015; 281:20140580. [PMID: 24966311 DOI: 10.1098/rspb.2014.0580] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Menopause remains an evolutionary puzzle, as humans are unique among primates in having a long post-fertile lifespan. One model proposes that intergenerational conflict in patrilocal populations favours female reproductive cessation. This model predicts that women should experience menopause earlier in groups with an evolutionary history of patrilocality compared with matrilocal groups. Using data from the Indonesia Family Life Survey, we test this model at multiple timescales: deep historical time, comparing age at menopause in ancestrally patrilocal Chinese Indonesians with ancestrally matrilocal Austronesian Indonesians; more recent historical time, comparing age at menopause in ethnic groups with differing postmarital residence within Indonesia and finally, analysing age at menopause at an individual-level, assuming a woman facultatively adjusts her age at menopause based on her postmarital residence. We find a significant effect only at the intermediate timescale where, contrary to predictions, ethnic groups with a history of multilocal postnuptial residence (where couples choose where to live) have the slowest progression to menopause, whereas matrilocal and patrilocal ethnic groups have similar progression rates. Multilocal residence may reduce intergenerational conflicts between women, thus influencing reproductive behaviour, but our results provide no support for the female-dispersal model of intergenerational conflict as an explanation of menopause.
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Affiliation(s)
- Kristin Snopkowski
- Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Cristina Moya
- Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Rebecca Sear
- Department of Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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26
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Gluckman PD, Low FM, Buklijas T, Hanson MA, Beedle AS. How evolutionary principles improve the understanding of human health and disease. Evol Appl 2015; 4:249-63. [PMID: 25567971 PMCID: PMC3352556 DOI: 10.1111/j.1752-4571.2010.00164.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 09/19/2010] [Indexed: 02/06/2023] Open
Abstract
An appreciation of the fundamental principles of evolutionary biology provides new insights into major diseases and enables an integrated understanding of human biology and medicine. However, there is a lack of awareness of their importance amongst physicians, medical researchers, and educators, all of whom tend to focus on the mechanistic (proximate) basis for disease, excluding consideration of evolutionary (ultimate) reasons. The key principles of evolutionary medicine are that selection acts on fitness, not health or longevity; that our evolutionary history does not cause disease, but rather impacts on our risk of disease in particular environments; and that we are now living in novel environments compared to those in which we evolved. We consider these evolutionary principles in conjunction with population genetics and describe several pathways by which evolutionary processes can affect disease risk. These perspectives provide a more cohesive framework for gaining insights into the determinants of health and disease. Coupled with complementary insights offered by advances in genomic, epigenetic, and developmental biology research, evolutionary perspectives offer an important addition to understanding disease. Further, there are a number of aspects of evolutionary medicine that can add considerably to studies in other domains of contemporary evolutionary studies.
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Affiliation(s)
- Peter D Gluckman
- Centre for Human Evolution, Adaptation and Disease, Liggins Institute, The University of Auckland Auckland, New Zealand
| | - Felicia M Low
- Centre for Human Evolution, Adaptation and Disease, Liggins Institute, The University of Auckland Auckland, New Zealand
| | - Tatjana Buklijas
- Centre for Human Evolution, Adaptation and Disease, Liggins Institute, The University of Auckland Auckland, New Zealand
| | - Mark A Hanson
- Institute of Developmental Sciences, University of Southampton, Mailpoint 887, Southampton General Hospital Southampton, UK
| | - Alan S Beedle
- Centre for Human Evolution, Adaptation and Disease, Liggins Institute, The University of Auckland Auckland, New Zealand
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27
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Blaser MJ, Webb GF. Host demise as a beneficial function of indigenous microbiota in human hosts. mBio 2014; 5:e02262-14. [PMID: 25516618 PMCID: PMC4271553 DOI: 10.1128/mbio.02262-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/14/2014] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED The age structure of human populations is exceptional among animal species. Unlike with most species, human juvenility is extremely extended, and death is not coincident with the end of the reproductive period. We examine the age structure of early humans with models that reveal an extraordinary balance of human fertility and mortality. We hypothesize that the age structure of early humans was maintained by mechanisms incorporating the programmed death of senescent individuals, including by means of interactions with their indigenous microorganisms. First, before and during reproductive life, there was selection for microbes that preserve host function through regulation of energy homeostasis, promotion of fecundity, and defense against competing high-grade pathogens. Second, we hypothesize that after reproductive life, there was selection for organisms that contribute to host demise. While deleterious to the individual, the presence of such interplay may be salutary for the overall host population in terms of resource utilization, resistance to periodic diminutions in the food supply, and epidemics due to high-grade pathogens. We provide deterministic mathematical models based on age-structured populations that illustrate the dynamics of such relationships and explore the relevant parameter values within which population viability is maintained. We argue that the age structure of early humans was robust in its balance of the juvenile, reproductive-age, and senescent classes. These concepts are relevant to issues in modern human longevity, including inflammation-induced neoplasia and degenerative diseases of the elderly, which are a legacy of human evolution. IMPORTANCE The extended longevity of modern humans is a very recent societal artifact, although it is inherent in human evolution. The age structure of early humans was balanced by fertility and mortality, with an exceptionally prolonged juvenility. We examined the role of indigenous microbes in early humans as fundamental contributors to this age structure. We hypothesize that the human microbiome evolved mechanisms specific to the mortality of senescent individuals among early humans because their mortality contributed to the stability of the general population. The hypothesis that we present provides new bases for modern medical problems, such as inflammation-induced neoplasia and degenerative diseases of the elderly. We postulate that these mechanisms evolved because they contributed to the stability of early human populations, but their legacy is now a burden on human longevity in the changed modern world.
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Affiliation(s)
| | - Glenn F Webb
- Department of Mathematics, Vanderbilt University, Nashville, Tennessee, USA
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Abstract
Why do humans live longer than other higher primates? Why do women live longer than men? What is the significance of the menopause? Answers to these questions may be sought by reference to the mechanisms by which human aging might have evolved. Here, an evolutionary hypothesis is presented that could answer all three questions, based on the following suppositions. First, that the evolution of increased human longevity was driven by increased late-life reproduction by men in polygynous primordial societies. Second, that the lack of a corresponding increase in female reproductive lifespan reflects evolutionary constraint on late-life oocyte production. Third, that antagonistic pleiotropy acting on androgen-generated secondary sexual characteristics in men increased reproductive success earlier in life, but shortened lifespan. That the gender gap in aging is attributable to androgens appears more likely given a recent report of exceptional longevity in eunuchs. Yet androgen depletion therapy, now used to treat prostatic hyperplasia, appears to accelerate other aspects of aging (e.g. cardiovascular disease). One possibility is that low levels of androgens throughout life reduces aging rate, but late-life androgen depletion does not.
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Affiliation(s)
- David Gems
- Institute of Healthy Ageing, and Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
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29
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Blagosklonny MV. Aging is not programmed: genetic pseudo-program is a shadow of developmental growth. Cell Cycle 2013; 12:3736-42. [PMID: 24240128 PMCID: PMC3905065 DOI: 10.4161/cc.27188] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Aging is not and cannot be programmed. Instead, aging is a continuation of developmental growth, driven by genetic pathways such as mTOR. Ironically, this is often misunderstood as a sort of programmed aging. In contrast, aging is a purposeless quasi-program or, figuratively, a shadow of actual programs. “The brightest flame casts the darkest shadow.” -George Martin
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Abstract
Human menopause is an unsolved evolutionary puzzle, and relationships among the factors that produced it remain understood poorly. Classic theory, involving a one-sex (female) model of human demography, suggests that genes imparting deleterious effects on post-reproductive survival will accumulate. Thus, a 'death barrier' should emerge beyond the maximum age for female reproduction. Under this scenario, few women would experience menopause (decreased fertility with continued survival) because few would survive much longer than they reproduced. However, no death barrier is observed in human populations. Subsequent theoretical research has shown that two-sex models, including male fertility at older ages, avoid the death barrier. Here we use a stochastic, two-sex computational model implemented by computer simulation to show how male mating preference for younger females could lead to the accumulation of mutations deleterious to female fertility and thus produce a menopausal period. Our model requires neither the initial assumption of a decline in older female fertility nor the effects of inclusive fitness through which older, non-reproducing women assist in the reproductive efforts of younger women. Our model helps to explain why such effects, observed in many societies, may be insufficient factors in elucidating the origin of menopause.
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Klepsatel P, Gáliková M, De Maio N, Ricci S, Schlötterer C, Flatt T. Reproductive and post-reproductive life history of wild-caught Drosophila melanogaster
under laboratory conditions. J Evol Biol 2013; 26:1508-20. [DOI: 10.1111/jeb.12155] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Accepted: 03/08/2013] [Indexed: 11/28/2022]
Affiliation(s)
- P. Klepsatel
- Institut für Populationsgenetik; Vetmeduni Vienna; Vienna Austria
| | - M. Gáliková
- Institut für Populationsgenetik; Vetmeduni Vienna; Vienna Austria
| | - N. De Maio
- Institut für Populationsgenetik; Vetmeduni Vienna; Vienna Austria
| | - S. Ricci
- Dipartimento di Matematica; Università di Pisa; Pisa Italy
| | - C. Schlötterer
- Institut für Populationsgenetik; Vetmeduni Vienna; Vienna Austria
| | - T. Flatt
- Institut für Populationsgenetik; Vetmeduni Vienna; Vienna Austria
- Wissenschaftskolleg zu Berlin; Berlin Germany
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32
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Cyrus CCY, Lee RD. On the evolution of intergenerational division of labor, menopause and transfers among adults and offspring. J Theor Biol 2013; 332:171-80. [PMID: 23648187 DOI: 10.1016/j.jtbi.2013.04.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 04/22/2013] [Accepted: 04/24/2013] [Indexed: 11/19/2022]
Abstract
We explain how upward transfers from adult children to their elderly parents might evolve as an interrelated feature of a deepening intergenerational division of labor. Humans have a particularly long period of juvenile dependence requiring both food and care time provided mainly by younger and older adults. We suggest that the division of labor evolves to exploit comparative advantage between young and old adults in fertility, childcare and foraging. Eventually the evolving division of labor reaches a limit when the grandmother's fertility reaches zero (menopause). Continuing, it may hit another limit when the grandmother's foraging time has been reduced to her subsistence needs. Further specialization can occur only with food transfers to the grandmother, enabling her to reduce her foraging time to concentrate on additional childcare. We prove that this outcome can arise only after menopause has evolved. We describe the conditions necessary for both group selection (comparative steady state reproductive fitness) and individual selection (successful invasion by a mutation), and interpret these conditions in terms of comparative advantages.
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Affiliation(s)
- Chu C Y Cyrus
- Institute of Economics, Academia Sinica, National Taiwan University, Taiwan.
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33
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Gowdy J, Krall L. Agriculture as a major evolutionary transition to human ultrasociality. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s10818-013-9156-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Menopause: No support for an evolutionary explanation among historical Norwegians. Exp Gerontol 2013; 48:408-13. [DOI: 10.1016/j.exger.2013.02.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 12/20/2012] [Accepted: 02/03/2013] [Indexed: 11/21/2022]
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Leontieva OV, Paszkiewicz GM, Blagosklonny MV. Mechanistic or mammalian target of rapamycin (mTOR) may determine robustness in young male mice at the cost of accelerated aging. Aging (Albany NY) 2012; 4:899-916. [PMID: 23443503 PMCID: PMC3615157 DOI: 10.18632/aging.100528] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/20/2012] [Indexed: 01/01/2023]
Abstract
Males, who are bigger and stronger than females, live shorter in most species from flies to mammals including humans. Cellular mass growth is driven in part by mTOR (Target of Rapamycin). When developmental growth is completed, then, instead of growth, mTOR drives aging, manifested by increased cellular functions, such as hyper-secretion by fibroblasts, thus altering homeostasis, leading to age-related diseases and death. We hypothesize that MTOR activity is elevated in male mice compared with females. Noteworthy, 6 months old males were 28 % heavier than females. Also levels of phosphorylated S6 (pS6) and phospho-AKT (p-AKT, Ser 473), markers of the mTOR activity, were higher in male organs tested. Levels of pS6 were highly variable among mice and correlated with body weight and p-AKT. With age, the difference between levels of pS6 between sexes tended to minimize, albeit males still had hyperactive mTOR. Unlike fasting, the intraperitoneal (i.p.) administration of rapamycin eliminated pS6 in all organs of all females measured by immunoblotting and immunohistochemistry without affecting p-AKT and blood insulin. Although i.p. rapamycin dramatically decreased levels of pS6 in males too, it was still detectable by immunoblotting upon longer exposure. Our study demonstrated that both tissue p-AKT and pS6 were higher in young male mice and were associated with increased body weight and insulin. These data can explain bigger body size and faster aging in males. Our data suggest higher efficacy of rapamycin compared to fasting. Higher sensitivity of females to rapamycin may explain more pronounced life extension by rapamycin observed in females compared to males in several studies.
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Affiliation(s)
- Olga V Leontieva
- Department of Cell Stress Biology, Roswell Park Cancer Institute, BLSC, L3-312, Elm and Carlton Streets, Buffalo, NY 14263, USA
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36
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Lahdenperä M, Gillespie DOS, Lummaa V, Russell AF. Severe intergenerational reproductive conflict and the evolution of menopause. Ecol Lett 2012; 15:1283-1290. [DOI: 10.1111/j.1461-0248.2012.01851.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 05/10/2012] [Accepted: 07/19/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Mirkka Lahdenperä
- Section of Ecology; Department of Biology; University of Turku; FIN-20014 Turku Finland
| | | | - Virpi Lummaa
- Department of Animal & Plant Sciences; University of Sheffield; Sheffield S10 2TN UK
- Wissenschaftskolleg zu Berlin; Institute for Advanced Study; Wallotstraße 19 D-14193 Berlin Germany
| | - Andrew F. Russell
- Centre for Ecology & Conservation; College of Life & Environmental Sciences; University of Exeter; Penryn TR10 9EZ UK
- Station d'Ecologie Expérimentale du CNRS USR 2936; 09200 Moulis France
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Kachel AF, Premo LS. Disentangling the Evolution of Early and Late Life History Traits in Humans. Evol Biol 2012. [DOI: 10.1007/s11692-012-9169-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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38
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Abstract
Understanding why and how senescence evolved is of great importance in investigating the multiple, complex mechanisms that influence the course of ageing in humans and other organisms. Compelling arguments eliminate the idea that death is generally programmed by genes for ageing, but there is still a widespread tendency to interpret data in terms of loosely defined 'age regulation', which does not usually make either evolutionary or mechanistic sense. This review critically addresses the role of natural selection in shaping ageing within the life history and examines the implications for research on genetic pathways that influence the life span. It is recognised that in exceptional circumstances the possibility exists for selection to favour limiting survival. In acknowledging that, at least in theory, ageing might occasionally be adaptive, however, the high barriers to validating actual instances of adaptive ageing are made clear.
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Tully T, Lambert A. THE EVOLUTION OF POSTREPRODUCTIVE LIFE SPAN AS AN INSURANCE AGAINST INDETERMINACY. Evolution 2011; 65:3013-20. [DOI: 10.1111/j.1558-5646.2011.01347.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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Kachel AF, Premo LS, Hublin JJ. Grandmothering and natural selection. Proc Biol Sci 2011; 278:384-91. [PMID: 20739319 PMCID: PMC3013409 DOI: 10.1098/rspb.2010.1247] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 08/05/2010] [Indexed: 11/12/2022] Open
Abstract
Humans are unique among primates in that women regularly outlive their reproductive period by decades. The grandmother hypothesis proposes that natural selection increased the length of the human post-menopausal period-and, thus, extended longevity-as a result of the inclusive fitness benefits of grandmothering. However, it has yet to be demonstrated that the inclusive fitness benefits associated with grandmothering are large enough to warrant this explanation. Here, we show that the inclusive fitness benefits are too small to affect the evolution of longevity under a wide range of conditions in simulated populations. This is due in large part to the relatively weak selection that applies to women near or beyond the end of their reproductive period. However, we find that grandmothers can facilitate the evolution of a shorter reproductive period when their help decreases the weaning age of their matrilineal grandchildren. Because selection favours a shorter reproductive period in the presence of shorter interbirth intervals, this finding holds true for any form of allocare that helps mothers resume cycling more quickly. We conclude that while grandmothering is unlikely to explain human-like longevity, allocare could have played an important role in shaping other unique aspects of human life history, such as a later age at first birth and a shorter female reproductive period.
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Affiliation(s)
- A Friederike Kachel
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
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41
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Kaptijn R, Thomese F, van Tilburg TG, Liefbroer AC. How Grandparents Matter: Support for the Cooperative Breeding Hypothesis in a Contemporary Dutch Population. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2010; 21:393-405. [PMID: 21212819 PMCID: PMC2995872 DOI: 10.1007/s12110-010-9098-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Low birth rates in developed societies reflect women's difficulties in combining work and motherhood. While demographic research has focused on the role of formal childcare in easing this dilemma, evolutionary theory points to the importance of kin. The cooperative breeding hypothesis states that the wider kin group has facilitated women's reproduction during our evolutionary history. This mechanism has been demonstrated in pre-industrial societies, but there is no direct evidence of beneficial effects of kin's support on parents' reproduction in modern societies. Using three-generation longitudinal data anchored in a sample of grandparents aged 55 and over in 1992 in the Netherlands, we show that childcare support from grandparents increases the probability that parents have additional children in the next 8 to 10 years. Grandparental childcare provided to a nephew or niece of childless children did not significantly increase the probability that those children started a family. These results suggest that childcare support by grandparents can enhance their children's reproductive success in modern societies and is an important factor in people's fertility decisions, along with the availability of formal childcare.
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Affiliation(s)
- Ralf Kaptijn
- Faculty of Social Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | | | | | - Aart C. Liefbroer
- Netherlands Interdisciplinary Demographic Institute, VU University Amsterdam, Amsterdam, The Netherlands
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Lahdenperä M, Russell AF, Tremblay M, Lummaa V. Selection on menopause in two premodern human populations: no evidence for the Mother Hypothesis. Evolution 2010; 65:476-89. [PMID: 20874739 DOI: 10.1111/j.1558-5646.2010.01142.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Evolutionary theory suggests that natural selection should synchronize senescence of reproductive and somatic systems. In some species, females show dramatic discordance in senescence rates in these systems, leading to a clear menopause coupled with prolonged postreproductive life span. The Mother Hypothesis proposes that menopause evolved to avoid higher reproductive-mediated mortality risk in late-life and ensure the survival of existing offspring. Despite substantial theoretical interest, the critical predictions of this hypothesis have never been fully tested in populations with natural fertility and mortality. Here, we provide an extensive test, investigating both short- and long-term consequences of mother loss for offspring, using multigenerational demographic datasets of premodern Finns and Canadians. We found no support for the Mother Hypothesis. First, although the risk of maternal death from childbirth increased from middle age, the risk only reached 1-2% at age 50 and was predicted to range between 2% and 8% by 70. Second, offspring were adversely affected by maternal loss only in their first two years (i.e., preweaning), having reduced survival probability in early childhood as well as ultimate life span and fitness. Dependent offspring were not affected by maternal death following weaning, either in the short- or long-term. We suggest that although mothers are required to ensure offspring survival preweaning in humans, maternal loss thereafter can be compensated by other family members. Our results indicate that maternal effects on dependent offspring are unlikely to explain the maintenance of menopause or prolonged postreproductive life span in women.
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Affiliation(s)
- Mirkka Lahdenperä
- Section of Ecology, Department of Biology, University of Turku, FIN-20014, Turku, Finland.
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Kirkwood TBL, Shanley DP. The connections between general and reproductive senescence and the evolutionary basis of menopause. Ann N Y Acad Sci 2010; 1204:21-9. [PMID: 20738272 DOI: 10.1111/j.1749-6632.2010.05520.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We consider the relationship between the factors responsible for the general biology of aging and those that specifically influence the aging of the reproductive system. To understand this relationship it is necessary to be clear about the evolutionary forces acting on both sets of factors. Only in this way can the correct causal connections be established. Of particular significance is the existence in some species of a distinct period of postreproductive life. This is most striking in the case of the human menopause, for which a particular combination of biological and sociobiological factors appear to be responsible.
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Affiliation(s)
- Thomas B L Kirkwood
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, UK.
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44
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Abstract
Women
live longer than men. Yet, it is believed that men do not age faster than
women but simply are weaker at every age. In contrast, I discuss that men
age faster. From evolutionary perspective, high accidental death rate in
young males is compatible with fast aging. Mechanistically, hyper-activated
mTOR (Target of Rapamycin) may render young males robust at the cost of
accelerated aging. But if women age slower, why then is it women who have
menopause? Some believe that menopause is programmed and purposeful
(grandmother theory). In contrast, I discuss how menopause is not
programmed but rather is an aimless continuation of the same program that
initially starts reproduction at puberty. This quasi-program causes
over-activation of female reproductive system, which is very vulnerable to
over-activation. Mechanisms of aging and menopause are discussed.
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Blagosklonny MV. Solving puzzles of aging: From disposable soma to signal-transduction pathways. RUSS J GEN CHEM+ 2010. [DOI: 10.1134/s1070363210070364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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46
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Altruistic colony defense by menopausal female insects. Curr Biol 2010; 20:1182-6. [PMID: 20619817 DOI: 10.1016/j.cub.2010.04.057] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2010] [Revised: 04/28/2010] [Accepted: 04/28/2010] [Indexed: 11/20/2022]
Abstract
Recent studies have suggested that an extended postreproductive life span, such as life after menopause in human females, will evolve when the indirect (kin-selected) fitness benefits from altruistic behavior are greater than the direct fitness benefits from continuing reproduction. Under some conditions in which postreproductive altruism is more beneficial and/or continuing reproduction is more costly, the postreproductive life span can be shaped by natural selection. However, indirect fitness benefits during postreproductive survival have been documented mainly in intelligent mammals such as humans and cetaceans, in which elder females possess enhanced social knowledge through learning. Here we show that postreproductive females of the gall-forming aphid Quadrartus yoshinomiyai (Nipponaphidini) can gain indirect fitness benefits through their altruistic colony defense. These females cease reproduction around the time of gall opening and defend the colony by sticking themselves to intruding predators with a waxy secretion that is accumulated in their body with aging. Our results suggest that the presence of an age-related trait for altruistic behavior promotes the evolution of postreproductive altruism in this social insect via kin selection under natural selection imposed by predators.
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Kuang H, Zhang L, Peng J, Chen Q. Premature ovarian failure, menopause and ovarian cancer, three nodes on the same string: Pten and other potential genes on the go. Med Hypotheses 2009; 73:961-2. [PMID: 19733443 DOI: 10.1016/j.mehy.2009.06.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2009] [Revised: 06/07/2009] [Accepted: 06/11/2009] [Indexed: 11/19/2022]
Abstract
BACKGROUND Why do women have menopause? The evolution of menopause has long been the puzzle and interest of sociologists regarding Darwinian fitness. However, in a biological/medical perspective, the underling drive force of menopause has never been provided in a satisfactory form. HYPOTHESIS AND RATIONALE It has been well established that the overall reproductive lifespan is reflected in the speed of ovarian primordial follicles depletion. And, every ovarian cycle involves disruption and regeneration of the ovarian epithelium, which is potentially mutagenic. In this regard, menopause could be evolved to protect reproductive organs from over-disruption-reconstruction cycling, as to preclude mutagenic tissue changes. Recent discoveries by tissue/cell specific deletion of one single gene (Pten) within different compartment of ovary have revealed strikingly distinct ovarian phenotypes, ranging from advanced primordial follicle depletion to neoplastic ovarian lesions. To explain the onset of menopause, here we propose a model that the relative amount/activity of Pten between different ovarian compartments (follicular, granulosa and epithelial cells) is spatiotemporally programmed, creating a "menopause tone" fine tuning the speed of follicle depletion and therefore the normal timing of menopause. While imbalanced expression of Pten within the ovary cause either pre-arrived menopause (premature ovarian failure) or over-menstrual cycles which are well recognized as a risk factor for ovarian (and other reproductive) cancer. This hypothesis, if validated, could help us understand ovarian aging and related diseases in a more integrated manner; they are just different nodes on the same string. And Pten could just be the tip of the iceberg involved in the regulation of "menopause tone".
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Affiliation(s)
- Haibin Kuang
- Department of Physiology, School of Medicine, Nanchang University, 461 Bayi Road, Nanchang 330006, China.
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Joyner-Matos J, Upadhyay A, Salomon MP, Grigaltchik V, Baer CF. Genetic (Co)variation for life span in rhabditid nematodes: role of mutation, selection, and history. J Gerontol A Biol Sci Med Sci 2009; 64:1134-45. [PMID: 19671885 DOI: 10.1093/gerona/glp112] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The evolutionary mechanisms maintaining genetic variation in life span, particularly post-reproductive life span, are poorly understood. We characterized the effects of spontaneous mutations on life span in the rhabditid nematodes Caenorhabditis elegans and C. briggsae and standing genetic variance for life span and correlation of life span with fitness in C. briggsae. Mutations decreased mean life span, a signature of directional selection. Mutational correlations between life span and fitness were consistently positive. The average selection coefficient against new mutations in C. briggsae was approximately 2% when homozygous. The pattern of phylogeographic variation in life span is inconsistent with global mutation-selection balance (MSB), but MSB appears to hold at the local level. Standing genetic correlations in C. briggsae reflect mutational correlations at a local scale but not at a broad phylogeographic level. At the local scale, results are broadly consistent with predictions of the "mutation accumulation" hypothesis for the evolution of aging.
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Affiliation(s)
- Joanna Joyner-Matos
- Department of Biology, Eastern Washington University, Cheney, WA 99004-2440, USA.
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50
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Rashidi A, Shanley D. Evolution of the menopause: life histories and mechanisms. ACTA ACUST UNITED AC 2009; 15:26-30. [DOI: 10.1258/mi.2009.009005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A long postreproductive lifespan is a characteristic feature in the life history of human females, which is not shared with other primates. The ultimate cause of menopause has been the focus of much study and has generated a number of evolutionary explanations, most prominently the mother and grandmother hypotheses. Generally, these theories propose that menopause was an adaptive response to changes that led to the divergence of humans from their ancestors, and are based on observations such as the long-dependency time of human infants, early age of weaning of human neonates, high maternal mortality, the supportive role of grandmothers in childcare, and intergroup female transfers. While ongoing debate continues to refine evolutionary theory, the proximate cause of menopause currently receives less attention. Our knowledge about the mechanisms underlying menopause has been largely confined to ovarian exhaustion, the progressive loss of oocytes beginning before birth and continuing to the age of menopause. Most efforts have to date been focused on fitting curves to the few data available, rather than trying to explain why the dynamics of oocyte depletion follows a particular pattern. A few recent studies have attempted to address this problem by demonstrating that oocyte dynamics is a regulated process under tight physiological control, e.g. that ovaries sense both number and quality of their oocytes. In this review we assess our current knowledge from an evolutionary perspective and emphasize the benefit of combining a mechanistic and life history approach.
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Affiliation(s)
- Armin Rashidi
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Daryl Shanley
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
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