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Huang JP, Wu SP, Chen WY, Pham GJ, Kuan YH. Genomic data revealed inbreeding despite a geographically connected stable effective population size since the Holocene in the protected Formosan Long-Arm Scarab beetle, Cheirotonus formosanus. J Hered 2024; 115:292-301. [PMID: 38364316 DOI: 10.1093/jhered/esae006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 02/08/2024] [Indexed: 02/18/2024] Open
Abstract
Biodiversity conservation is a top priority in the face of global environmental change, and the practical restoration of biodiversity has emerged as a key objective. Nevertheless, the question of how to effectively contribute to biodiversity restoration and identify suitable systems for such efforts continues to present major challenges. By using genome-wide SNP data, our study revealed that populations from different mountain ranges of the Formosan Long-Arm Scarab beetle, a flagship species that receives strict protection, exhibited a single genetic cluster with no subdivision. Additionally, our result implied an association between the demographic history and historical fluctuations in climate and environmental conditions. Furthermore, we showed that, despite a stable and moderately sized effective population over recent history, all the individuals we studied exhibited signs of genetic inbreeding. We argued that the current practice of protecting the species as one evolutionarily significant unit remains the best conservation plan and that recent habitat change may have led to the pattern of significant inbreeding. We closed by emphasizing the importance of conservation genetic studies in guiding policy decisions and highlighting the potential of genomic data for identifying ideal empirical systems for genetic rescue, or assisted gene flow studies.
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Affiliation(s)
- Jen-Pan Huang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Shu-Ping Wu
- Department of Earth and Life Science, University of Taipei, Taipei, Taiwan
| | - Wei-Yun Chen
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Guan Jie Pham
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Hsiu Kuan
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
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Al Hikmani H, van Oosterhout C, Birley T, Labisko J, Jackson HA, Spalton A, Tollington S, Groombridge JJ. Can genetic rescue help save Arabia's last big cat? Evol Appl 2024; 17:e13701. [PMID: 38784837 PMCID: PMC11113348 DOI: 10.1111/eva.13701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/01/2024] [Accepted: 04/10/2024] [Indexed: 05/25/2024] Open
Abstract
Genetic diversity underpins evolutionary potential that is essential for the long-term viability of wildlife populations. Captive populations harbor genetic diversity potentially lost in the wild, which could be valuable for release programs and genetic rescue. The Critically Endangered Arabian leopard (Panthera pardus nimr) has disappeared from most of its former range across the Arabian Peninsula, with fewer than 120 individuals left in the wild, and an additional 64 leopards in captivity. We (i) examine genetic diversity in the wild and captive populations to identify global patterns of genetic diversity and structure; (ii) estimate the size of the remaining leopard population across the Dhofar mountains of Oman using spatially explicit capture-recapture models on DNA and camera trap data, and (iii) explore the impact of genetic rescue using three complementary computer modeling approaches. We estimated a population size of 51 (95% CI 32-79) in the Dhofar mountains and found that 8 out of 25 microsatellite alleles present in eight loci in captive leopards were undetected in the wild. This includes two alleles present only in captive founders known to have been wild-sourced from Yemen, which suggests that this captive population represents an important source for genetic rescue. We then assessed the benefits of reintroducing novel genetic diversity into the wild population as well as the risks of elevating the genetic load through the release of captive-bred individuals. Simulations indicate that genetic rescue can improve the long-term viability of the wild population by reducing its genetic load and realized load. The model also suggests that the genetic load has been partly purged in the captive population, potentially making it a valuable source population for genetic rescue. However, the greater loss of its genetic diversity could exacerbate genomic erosion of the wild population during a rescue program, and these risks and benefits should be carefully evaluated. An important next step in the recovery of the Arabian leopard is to empirically validate these conclusions, implement and monitor a genomics-informed management plan, and optimize a strategy for genetic rescue as a tool to recover Arabia's last big cat.
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Affiliation(s)
- Hadi Al Hikmani
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Division of Human and Social SciencesUniversity of KentCanterburyKentUK
- Office for Conservation of the EnvironmentDiwan of Royal CourtMuscatOman
- The Royal Commission for AlUlaAlUlaSaudi Arabia
| | - Cock van Oosterhout
- School of Environmental SciencesUniversity of East Anglia, Norwich Research ParkNorwichUK
| | - Thomas Birley
- School of Environmental SciencesUniversity of East Anglia, Norwich Research ParkNorwichUK
| | - Jim Labisko
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Division of Human and Social SciencesUniversity of KentCanterburyKentUK
- Centre for Biodiversity and Environment Research, Research Department of Genetics, Evolution and EnvironmentUniversity College LondonLondonUK
- Island Biodiversity and Conservation CentreUniversity of SeychellesVictoriaSeychelles
- Department of Life SciencesThe Natural History MuseumLondonUK
| | - Hazel A. Jackson
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Division of Human and Social SciencesUniversity of KentCanterburyKentUK
| | | | - Simon Tollington
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Division of Human and Social SciencesUniversity of KentCanterburyKentUK
- School of Animal Rural and Environmental SciencesNottingham Trent UniversityNottinghamUK
| | - Jim J. Groombridge
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, Division of Human and Social SciencesUniversity of KentCanterburyKentUK
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Kyriazis CC, Serieys LE, Bishop JM, Drouilly M, Viljoen S, Wayne RK, Lohmueller KE. The influence of gene flow on population viability in an isolated urban caracal population. Mol Ecol 2024; 33:e17346. [PMID: 38581173 PMCID: PMC11035096 DOI: 10.1111/mec.17346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 01/23/2024] [Accepted: 03/26/2024] [Indexed: 04/08/2024]
Abstract
Wildlife populations are becoming increasingly fragmented by anthropogenic development. Small and isolated populations often face an elevated risk of extinction, in part due to inbreeding depression. Here, we examine the genomic consequences of urbanization in a caracal (Caracal caracal) population that has become isolated in the Cape Peninsula region of the City of Cape Town, South Africa, and is thought to number ~50 individuals. We document low levels of migration into the population over the past ~75 years, with an estimated rate of 1.3 effective migrants per generation. As a consequence of this isolation and small population size, levels of inbreeding are elevated in the contemporary Cape Peninsula population (mean FROH = 0.20). Inbreeding primarily manifests as long runs of homozygosity >10 Mb, consistent with the effects of isolation due to the rapid recent growth of Cape Town. To explore how reduced migration and elevated inbreeding may impact future population dynamics, we parameterized an eco-evolutionary simulation model. We find that if migration rates do not change in the future, the population is expected to decline, though with a low projected risk of extinction. However, if migration rates decline or anthropogenic mortality rates increase, the potential risk of extinction is greatly elevated. To avert a population decline, we suggest that translocating migrants into the Cape Peninsula to initiate a genetic rescue may be warranted in the near future. Our analysis highlights the utility of genomic datasets coupled with computational simulation models for investigating the influence of gene flow on population viability.
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Affiliation(s)
- Christopher C. Kyriazis
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Laurel E.K. Serieys
- Panthera, 8 W 40th St, 18th Floor, New York, NY 10018, USA
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - Jacqueline M. Bishop
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - Marine Drouilly
- Panthera, 8 W 40th St, 18th Floor, New York, NY 10018, USA
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
- Centre for Social Science Research, University of Cape Town, Rondebosch, 7701, South Africa
| | - Storme Viljoen
- Institute for Communities and Wildlife in Africa, Department of Biological Sciences, University of Cape Town, Rondebosch, 7701, South Africa
| | - Robert K. Wayne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Kirk E. Lohmueller
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
- Interdepartmental Program in Bioinformatics, University of California, Los Angeles, CA 90095, USA
- Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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Pavlova A, Schneller NM, Lintermans M, Beitzel M, Robledo‐Ruiz DA, Sunnucks P. Planning and implementing genetic rescue of an endangered freshwater fish population in a regulated river, where low flow reduces breeding opportunities and may trigger inbreeding depression. Evol Appl 2024; 17:e13679. [PMID: 38617824 PMCID: PMC11009430 DOI: 10.1111/eva.13679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 02/11/2024] [Accepted: 02/26/2024] [Indexed: 04/16/2024] Open
Abstract
Augmenting depleted genetic diversity can improve the fitness and evolutionary potential of wildlife populations, but developing effective management approaches requires genetically monitored test cases. One such case is the small, isolated and inbred Cotter River population of an endangered Australian freshwater fish, the Macquarie perch Macquaria australasica, which over 3 years (2017-2019) received 71 translocated migrants from a closely related, genetically more diverse population. We used genetic monitoring to test whether immigrants bred, interbred with local fish and augmented population genetic diversity. We also investigated whether levels of river flow affected recruitment, inbreeding depression and juvenile dispersal. Fish length was used to estimate the age, birth year cohort and growth of 524 individuals born between 2016 and 2020 under variable flow conditions. DArT genome-wide genotypes were used to assess individual ancestry, heterozygosity, short-term effective population size and identify parent-offspring and full-sibling families. Of 442 individuals born after translocations commenced, only two (0.45%) were of mixed ancestry; these were half-sibs with one translocated parent in common. Numbers of breeders and genetic diversity for five birth year cohorts of the Cotter River fish were low, especially in low-flow years. Additionally, individuals born in the year of lowest flow evidently suffered from inbreeding depression for juvenile growth. The year of highest flow was associated with the largest number of breeders, lowest inbreeding in the offspring and greatest juvenile dispersal distances. Genetic diversity decreased in the upstream direction, flagging restricted access of breeders to the most upstream breeding sites, exacerbated by low river flow. Our results suggest that the effectiveness of translocations could be increased by focussing on upstream sites and moving more individuals per year; using riverine sources should be considered. Our results indicate that river flow sufficient to facilitate fish movement through the system would increase the number of breeders, promote individuals' growth, reduce inbreeding depression and promote genetic rescue.
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Affiliation(s)
- Alexandra Pavlova
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Nadja M. Schneller
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
| | - Mark Lintermans
- Centre for Applied Water ScienceInstitute for Applied Ecology, University of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Matt Beitzel
- Environment, Planning & Sustainable Development Directorate (ACT Government)CanberraAustralian Capital TerritoryAustralia
| | | | - Paul Sunnucks
- School of Biological SciencesMonash UniversityMelbourneVictoriaAustralia
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Clark MI, Fitzpatrick SW, Bradburd GS. Pitfalls and windfalls of detecting demographic declines using population genetics in long-lived species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.27.586886. [PMID: 38585961 PMCID: PMC10996660 DOI: 10.1101/2024.03.27.586886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Detecting recent demographic changes is a crucial component of species conservation and management, as many natural populations face declines due to anthropogenic habitat alteration and climate change. Genetic methods allow researchers to detect changes in effective population size (N e ) from sampling at a single timepoint. However, in species with long lifespans, there is a lag between the start of a decline in a population and the resulting decrease in genetic diversity. This lag slows the rate at which diversity is lost, and therefore makes it difficult to detect recent declines using genetic data. However, the genomes of old individuals can provide a window into the past, and can be compared to those of younger individuals, a contrast that may help reveal recent demographic declines. To test whether comparing the genomes of young and old individuals can help infer recent demographic bottlenecks, we use forward-time, individual-based simulations with varying mean individual lifespans and extents of generational overlap. We find that age information can be used to aid in the detection of demographic declines when the decline has been severe. When average lifespan is long, comparing young and old individuals from a single timepoint has greater power to detect a recent (within the last 50 years) bottleneck event than comparing individuals sampled at different points in time. Our results demonstrate how longevity and generational overlap can be both a hindrance and a boon to detecting recent demographic declines from population genomic data.
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Zamudio KR. Conservation genomics: Current applications and future directions. J Hered 2023; 114:297-299. [PMID: 37208804 DOI: 10.1093/jhered/esad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Affiliation(s)
- Kelly R Zamudio
- Biodiversity Center and Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, United States
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