Three hundred years of low non-paternity in a human population

When cuckoldry is frequent we can expect fathers to withhold investment in offspring that may not be theirs. Human paternal investment can be substantial and is in line with observations from tens of thousands of conceptions that suggest that cuckoldry is rare in humans. The generality of this claim seems to be in question as the rate of cuckoldry varies across populations and studies have mostly been on Western populations. Two additional factors complicate our conclusions, (1) current estimates of the rate of cuckoldry in humans may not reflect our past behaviour as adultery can be concealed by the use of contraceptives; and (2) it is difficult to obtain samples that are random with respect to their paternity certainty. Studies that combine genealogies with Y-chromosome haplotyping are able to circumvent some of these problems by probing into humans' historical behaviour. Here we use this approach to investigate 1273 conceptions over a period of 330 years in 23 families of the Afrikaner population in South Africa. We use haplotype frequency and diversity and coalescent simulations to show that the male population did not undergo a severe bottleneck and that paternity exclusion rates are high for this population. The rate of cuckoldry in this Western population was 0.9% (95% confidence interval 0.4-1.5%), and we argue that given the current data on historical populations we have to conclude that, at least for Western human populations, cuckoldry rate is probably in the range of 1%.

Relationships of maternal and paternal anthropometry with neonatal body size, proportions and adiposity in an Australian cohort

The patterns of association between maternal or paternal and neonatal phenotype may offer insight into how neonatal characteristics are shaped by evolutionary processes, such as conflicting parental interests in fetal investment and obstetric constraints. Paternal interests are theoretically served by maximizing fetal growth, and maternal interests by managing investment in current and future offspring, but whether paternal and maternal influences act on different components of overall size is unknown. We tested whether parents' prepregnancy height and body mass index (BMI) were related to neonatal anthropometry (birthweight, head circumference, absolute and proportional limb segment and trunk lengths, subcutaneous fat) among 1,041 Australian neonates using stepwise linear regression. Maternal and paternal height and maternal BMI were associated with birthweight. Paternal height related to offspring forearm and lower leg lengths, maternal height and BMI to neonatal head circumference, and maternal BMI to offspring adiposity. Principal components analysis identified three components of variability reflecting neonatal “head and trunk skeletal size,” “adiposity,” and “limb lengths.” Regression analyses of the component scores supported the associations of head and trunk size or adiposity with maternal anthropometry, and limb lengths with paternal anthropometry. Our results suggest that while neonatal fatness reflects environmental conditions (maternal physiology), head circumference and limb and trunk lengths show differing associations with parental anthropometry. These patterns may reflect genetics, parental imprinting and environmental influences in a manner consistent with parental conflicts of interest. Paternal height may relate to neonatal limb length as a means of increasing fetal growth without exacerbating the risk of obstetric complications. Am J Phys Anthropol 156:625–636, 2015.

Genetic genealogy reveals true Y haplogroup of House of Bourbon contradicting recent identification of the presumed remains of two French Kings

Genetic analysis strongly increases the opportunity to identify skeletal remains or other biological samples from historical figures. However, validation of this identification is essential and should be done by DNA typing of living relatives. Based on the similarity of a limited set of Y-STRs, a blood sample and a head were recently identified as those belonging respectively to King Louis XVI and his paternal ancestor King Henry IV. Here, we collected DNA samples from three living males of the House of Bourbon to validate the since then controversial identification of these remains. The three living relatives revealed the Bourbon's Y-chromosomal variant on a high phylogenetic resolution for several members of the lineage between Henry IV and Louis XVI. This 'true' Bourbon's variant is different from the published Y-STR profiles of the blood as well as of the head. The earlier identifications of these samples can therefore not be validated. Moreover, matrilineal genealogical data revealed that the published mtDNA sequence of the head was also different from the one of a series of relatives. This therefore leads to the conclusion that the analyzed samples were not from the French kings. Our study once again demonstrated that in order to realize an accurate genetic identification of historical remains DNA typing of living persons, who are paternally or maternally related with the presumed donor of the samples, is required.

Adolescent grandchildren's perceptions of grandparents' involvement in UK: an interpretation from life course and evolutionary theory perspective

In this article, we study grandparental involvement from the viewpoint of evolutionary theory and sociological life course perception. We have used 'the Involved Grandparenting and Child Well-Being 2007' survey, which is the first nationally representative sample of British and Welsh adolescents aged 11-16 (n = 1,488). First, we explore with the descriptive statistics the amount of grandparental involvement reported by adolescents. The result follows the predicted pattern: maternal grandparent is reported to involve in a grandchild's life the most, second maternal grandfather, third paternal grandmother and the last paternal grandfather. Second, we focus more closely on separate grandparents and show with four linear regression models which factors are connected to each grandparent's involvement. Grandchild's age, grandparent's health, grandparent's labour force participation and distance between a grandparent and a grandchild were factors that have similar effects in relation to all grandparents. Marital status mattered only for grandfathers, whereas family structure of a grandchild has opposite effects in relation to maternal and paternal grandparents. Grandchild's sex, grandparent's age, the number of grandchildren and the number of living grandparents all mattered, but only with respect to some grandparents. The study shows that it is advantageous to merge sociological and evolutionary viewpoints when studying a grandparental involvement in a modern society.

Detection of uniparental isodisomy in autosomal recessive mitochondrial DNA depletion syndrome by high-density SNP array analysis

Mitochondrial DNA (mtDNA) depletion syndrome encompasses a heterogeneous group of disorders characterized by a reduction in the mtDNA copy number. We identified two patients with clinical presentations consistent with mtDNA depletion syndrome (MDS), who were subsequently found to have apparently homozygous point mutations in TYMP and DGUOK, two of the nine nuclear genes commonly associated with these disorders. Further sequence analyses of parents indicated that in each case only one parent; the mother of the first and the father of the second, was a heterozygous carrier of the mutation identified in the affected child. The presence of underlying deletions was ruled out by use of a custom target array comparative genomic hybridization (CGH) platform. A high-density single-nucleotide polymorphism (SNP) array analysis revealed that the first patient had a region of copy-neutral absence of heterozygosity (AOH) consistent with segmental isodisomy for an 11.3 Mb region at the long-arm terminus of chromosome 22 (including the TYMP gene), and the second patient had results consistent with complete isodisomy of chromosome 2 (where the DGUOK gene is located). The combined sequencing, array CGH and SNP array approaches have demonstrated the first cases of MDS due to uniparental isodisomy. This diagnostic scenario also demonstrates the necessity of comprehensive examination of the underlying molecular defects of an apparently homozygous mutation in order to provide patients and their families with the most accurate molecular diagnosis and genetic counseling.

Pervasiveness of the IQ rise: a cross-temporal meta-analysis

BACKGROUND

Generational IQ gains in the general population (termed the Flynn effect) show an erratic pattern across different nations as well as across different domains of intelligence (fluid vs crystallized). Gains of fluid intelligence in different countries have been subject to extensive research, but less attention was directed towards gains of crystallized intelligence, probably due to evidence from the Anglo-American sphere suggesting only slight gains on this measure. In the present study, development of crystallized intelligence in the German speaking general population is assessed.

METHODOLOGY/PRINCIPAL FINDINGS

To investigate whether IQ gains for crystallized intelligence are in progress in German-speaking countries, two independent meta-analyses were performed. By means of a cited reference search in ISI Web of Science, all studies citing test manuals and review articles of two widely-used salient measures of crystallized intelligence were obtained. Additionally, the electronic database for German academic theses was searched to identify unpublished studies employing these tests. All studies reporting participants mean IQ or raw scores of at least one of the two measures were included in the present analyses, yielding over 500 studies (>1,000 samples; >45,000 individuals). We found a significant positive association between years of test performance and intelligence (1971-2007) amounting to about 3.5 IQ points per decade.

CONCLUSIONS/SIGNIFICANCE

This study clearly demonstrates that crystallized IQ gains are substantial and of comparable strength as Flynn effects typically observed for measures of fluid intelligence in Central Europe. Since mean IQ was assessed in a large number of small, non-representative samples, our evidence suggests a remarkable robustness of these gains. Moreover, in both meta-analyses strength of gains was virtually identical. On the whole, results of the present study demonstrate a pervasive and generalizing Flynn effect in German-speaking countries.