Hearing Sensitivity of Primates: Recurrent and Episodic Positive Selection in Hair Cells and Stereocilia Protein-Coding Genes.

The large spectrum of hearing sensitivity observed in primates results from the impact of environmental and behavioral pressures to optimize sound perception and localization. Although evidence of positive selection in auditory genes has been detected in mammals including in Hominoids, selection has never been investigated in other primates. We analyzed 123 genes highly expressed in the inner ear of 27 primate species and tested to what extent positive selection may have shaped these genes in the order Primates tree. We combined both site and branch-site tests to obtain a comprehensive picture of the positively selected genes (PSGs) involved in hearing sensitivity, and drew a detailed description of the most affected branches in the tree. We chose a conservative approach, and thus focused on confounding factors potentially affecting PSG signals (alignment, GC-biased gene conversion, duplications, heterogeneous sequencing qualities). Using site tests, we showed that around 12% of these genes are PSGs, an α selection value consistent with average human genome estimates (10-15%). Using branch-site tests, we showed that the primate tree is heterogeneously affected by positive selection, with the black snub-nosed monkey, the bushbaby, and the orangutan, being the most impacted branches. A large proportion of these genes is inclined to shape hair cells and stereocilia, which are involved in the mechanotransduction process, known to influence frequency perception. Adaptive selection, and more specifically recurrent adaptive evolution, could have acted in parallel on a set of genes (ADGRV1, USH2A, PCDH15, PTPRQ, and ATP8A2) involved in stereocilia growth and the whole complex of bundle links connecting them, in species across different habitats, including high altitude and nocturnal environments.

Subdividing Y-chromosome haplogroup R1a1 reveals Norse Viking dispersal lineages in Britain.

The influence of Viking-Age migrants to the British Isles is obvious in archaeological and place-names evidence, but their demographic impact has been unclear. Autosomal genetic analyses support Norse Viking contributions to parts of Britain, but show no signal corresponding to the Danelaw, the region under Scandinavian administrative control from the ninth to eleventh centuries. Y-chromosome haplogroup R1a1 has been considered as a possible marker for Viking migrations because of its high frequency in peninsular Scandinavia (Norway and Sweden). Here we select ten Y-SNPs to discriminate informatively among hg R1a1 sub-haplogroups in Europe, analyse these in 619 hg R1a1 Y chromosomes including 163 from the British Isles, and also type 23 short-tandem repeats (Y-STRs) to assess internal diversity. We find three specifically Western-European sub-haplogroups, two of which predominate in Norway and Sweden, and are also found in Britain; star-like features in the STR networks of these lineages indicate histories of expansion. We ask whether geographical distributions of hg R1a1 overall, and of the two sub-lineages in particular, correlate with regions of Scandinavian influence within Britain. Neither shows any frequency difference between regions that have higher (≥10%) or lower autosomal contributions from Norway and Sweden, but both are significantly overrepresented in the region corresponding to the Danelaw. These differences between autosomal and Y-chromosomal histories suggest either male-specific contribution, or the influence of patrilocality. Comparison of modern DNA with recently available ancient DNA data supports the interpretation that two sub-lineages of hg R1a1 spread with the Vikings from peninsular Scandinavia.

Predicting haplogroups using a versatile machine learning program (PredYMaLe) on a new mutationally balanced 32 Y-STR multiplex (CombYplex): Unlocking the full potential of the human STR mutation rate spectrum to estimate forensic parameters.

We developed a new mutationally well-balanced 32 Y-STR multiplex (CombYplex) together with a machine learning (ML) program PredYMaLe to assess the impact of STR mutability on haplogourp prediction, while respecting forensic community criteria (high DC/HD). We designed CombYplex around two sub-panels M1 and M2 characterized by average and high-mutation STR panels. Using these two sub-panels, we tested how our program PredYmale reacts to mutability when considering basal branches and, moving down, terminal branches. We tested first the discrimination capacity of CombYplex on 996 human samples using various forensic and statistical parameters and showed that its resolution is sufficient to separate haplogroup classes. In parallel, PredYMaLe was designed and used to test whether a ML approach can predict haplogroup classes from Y-STR profiles. Applied to our kit, SVM and Random Forest classifiers perform very well (average 97 %), better than Neural Network (average 91 %) and Bayesian methods (< 90 %). We observe heterogeneity in haplogroup assignation accuracy among classes, with most haplogroups having high prediction scores (99-100 %) and two (E1b1b and G) having lower scores (67 %). The small sample sizes of these classes explain the high tendency to misclassify the Y-profiles of these haplogroups; results were measurably improved as soon as more training data were added. We provide evidence that our ML approach is a robust method to accurately predict haplogroups when it is combined with a sufficient number of markers, well-balanced mutation rate Y-STR panels, and large ML training sets. Further research on confounding factors (such as CNV-STR or gene conversion) and ideal STR panels in regard to the branches analysed can be developed to help classifiers further optimize prediction scores.

ASGART: fast and parallel genome scale segmental duplications mapping.

Motivation: Segmental Duplications (SDs) are DNA fragments longer than 1 kbp, distributed within and between chromosomes and sharing more than 90% identity. Although they hold a significant role in genomic fluidity and adaptability, many key questions about their intrinsic characteristics and mutability remain unsolved due to the persistent difficulty of sequencing highly duplicated genomic regions. The recent development of long and linked-read NGS technologies will increase the need to search for SDs in genomes newly sequenced with these technics. The main limitation of SD analysis will soon be the availability of efficient detection software, to retrieve and compare SD genomic component between species or lineages. Results: In this paper, we present the open-source ASGART, 'A Segmental duplications Gathering And Refining Tool', developed to search for segmental duplications (SDs) in any assembled sequence. We have tested and benchmarked ASGART on five models organisms. Our results demonstrate ASGART's ability to extract SDs from any genome-wide sequence, regardless of genomic size or organizational complexity and quicker than any other software available. Availability and implementation: The online version of ASGART is available at http://asgart.irit.fr. The source code of ASGART is available both on the ASGART website and at https://github.com/delehef/asgart. Supplementary information: Supplementary data are available at Bioinformatics online.

About 42% of 154 remains from the "Battle of Le Mans", France (1793) belong to women and children: Morphological and genetic evidence.

Mass graves were discovered in Le Mans and 154 skeletons were exhumed, representing a remarkable historical series of human remains from western France. We aimed to characterise the age-class and sex of these subjects, and to determine whether their profile fits with that of the Catholic and Royal Army of Vendée, who fought against the Republican Army during the Battle of Le Mans (12th-13th December, 1793). This atypical army was composed of male soldiers, but also of civilian people who followed the troops, including the elderly, children and women. In total 154 skeletons from nine mass graves were exhumed from 2009 to 2010. Two morphological methods were used to determine the sex of the subjects: the Probabilist Sexual Diagnosis (DSP) and Secondary Sexual Diagnosis (DSS) methods. Samples were handled cautiously to avoid any pre-laboratory contamination. Molecular genetic sex-typing using a recently developed assay was used to maximise sex-diagnosis of the ancient DNA samples, and 97 successful profiles including immatures were generated. Using morphological and genetic data combined, we successfully determined the sex of 93% of the subjects; 62% were male and 31% female. About 87% of subjects could be considered adults (>18 years old), 6% adolescents (15-19 years old) and 7% infants (<15 years old). Our results of an unexpected population profile for an armed conflict (42% were women and children), in addition to traumatological and historical elements, tend to confirm that these subjects were involved in the Battle of Le Mans, either actively (Republican Army, the Catholic and Royal Army) or passively (collateral victims from the civilian population of Le Mans). They represent 5-6% of the estimated 2500-3000 victims.

Patrilineal populations show more male transmission of reproductive success than cognatic populations in Central Asia, which reduces their genetic diversity.

OBJECTIVE: The extent to which social organization of human societies impacts the patterns of genetic diversity remains an open question. Here, we investigate the transmission of reproductive success in patrilineal and cognatic populations from Central Asia using a coalescent approach. METHODS: We performed a study on the mitochondrial DNA (mtDNA) and Y chromosome polymorphism of patrilineal and cognatic populations from Central Asia. We reconstructed the gene genealogies in each population for both kind of markers and inferred the imbalance level of these genealogies, a parameter directly related to the level of transmission of reproductive success. RESULTS: This imbalance level appeared much stronger for the Y chromosome in patrilineal populations than in cognatic populations, while no difference was found for mtDNA. Furthermore, we showed that this imbalance level correlates negatively with Y-chromosomal, mtDNA, and autosomal genetic diversity. CONCLUSIONS: This shows that patrilineality might be one of the factors explaining the male transmission of reproductive success, which, in turn, lead to a reduction of genetic diversity. Thus, notwithstanding the fact that our population genetic approach clearly shows that there is a strong male-biased transmission of reproductive success in patrilineal societies, it also highlights the fact that a social process such as cultural transmission of reproductive success could play an important role in shaping human genetic diversity, although we cannot formally exclude that this transmission has also a genetic component.

Y-chromosome descent clusters and male differential reproductive success: young lineage expansions dominate Asian pastoral nomadic populations.

High-frequency microsatellite haplotypes of the male-specific Y-chromosome can signal past episodes of high reproductive success of particular men and their patrilineal descendants. Previously, two examples of such successful Y-lineages have been described in Asia, both associated with Altaic-speaking pastoral nomadic societies, and putatively linked to dynasties descending, respectively, from Genghis Khan and Giocangga. Here we surveyed a total of 5321 Y-chromosomes from 127 Asian populations, including novel Y-SNP and microsatellite data on 461 Central Asian males, to ask whether additional lineage expansions could be identified. Based on the most frequent eight-microsatellite haplotypes, we objectively defined 11 descent clusters (DCs), each within a specific haplogroup, that represent likely past instances of high male reproductive success, including the two previously identified cases. Analysis of the geographical patterns and ages of these DCs and their associated cultural characteristics showed that the most successful lineages are found both among sedentary agriculturalists and pastoral nomads, and expanded between 2100 BCE and 1100 CE. However, those with recent origins in the historical period are almost exclusively found in Altaic-speaking pastoral nomadic populations, which may reflect a shift in political organisation in pastoralist economies and a greater ease of transmission of Y-chromosomes through time and space facilitated by the use of horses.

Determined about sex: sex-testing in 45 primate species using a 2Y/1X sex-typing assay.

Sex-testing using molecular genetic technique is routinely used in the fields of forensics, population genetics and conservation biology. However, none of the assay used so far allows a non-ambiguous and successful sex determination for human and non-human primate species. The most widely used method, AMELY/X, and its alternatives suffer from a set of drawbacks in humans and can rarely be used in New World primate species. Here, we designed a new sex-typing assay using a multiplexed PCR amplification of UTX and UTY-homologous loci and combined male-specific SRY locus. This method was successfully tested on 1048 samples, including 82 non-human primates from 45 Anthropoidea and Lemuriformes species and 966 human samples from 24 populations (Africans, Europeans, and South Americans). This sex-typing method is applicable across all primate species tested from Hominoidea to Indriidae, and also on various populations with different background origins; it represents a robust and cheap sex-typing assay to be used both by the anthropologist and primatologist communities.

Identification of the remains of King Richard III.

In 2012, a skeleton was excavated at the presumed site of the Grey Friars friary in Leicester, the last-known resting place of King Richard III. Archaeological, osteological and radiocarbon dating data were consistent with these being his remains. Here we report DNA analyses of both the skeletal remains and living relatives of Richard III. We find a perfect mitochondrial DNA match between the sequence obtained from the remains and one living relative, and a single-base substitution when compared with a second relative. Y-chromosome haplotypes from male-line relatives and the remains do not match, which could be attributed to a false-paternity event occurring in any of the intervening generations. DNA-predicted hair and eye colour are consistent with Richard's appearance in an early portrait. We calculate likelihood ratios for the non-genetic and genetic data separately, and combined, and conclude that the evidence for the remains being those of Richard III is overwhelming.

Gene conversion violates the stepwise mutation model for microsatellites in y-chromosomal palindromic repeats.

The male-specific region of the human Y chromosome (MSY) contains eight large inverted repeats (palindromes), in which high-sequence similarity between repeat arms is maintained by gene conversion. These palindromes also harbor microsatellites, considered to evolve via a stepwise mutation model (SMM). Here, we ask whether gene conversion between palindrome microsatellites contributes to their mutational dynamics. First, we study the duplicated tetranucleotide microsatellite DYS385a,b lying in palindrome P4. We show, by comparing observed data with simulated data under a SMM within haplogroups, that observed heteroallelic combinations in which the modal repeat number difference between copies was large, can give rise to homoallelic combinations with zero-repeats difference, equivalent to many single-step mutations. These are unlikely to be generated under a strict SMM, suggesting the action of gene conversion. Second, we show that the intercopy repeat number difference for a large set of duplicated microsatellites in all palindromes in the MSY reference sequence is significantly reduced compared with that for nonpalindrome-duplicated microsatellites, suggesting that the former are characterized by unusual evolutionary dynamics. These observations indicate that gene conversion violates the SMM for microsatellites in palindromes, homogenizing copies within individual Y chromosomes, but increasing overall haplotype diversity among chromosomes within related groups.

Recombination dynamics of a human Y-chromosomal palindrome: rapid GC-biased gene conversion, multi-kilobase conversion tracts, and rare inversions.

The male-specific region of the human Y chromosome (MSY) includes eight large inverted repeats (palindromes) in which arm-to-arm similarity exceeds 99.9%, due to gene conversion activity. Here, we studied one of these palindromes, P6, in order to illuminate the dynamics of the gene conversion process. We genotyped ten paralogous sequence variants (PSVs) within the arms of P6 in 378 Y chromosomes whose evolutionary relationships within the SNP-defined Y phylogeny are known. This allowed the identification of 146 historical gene conversion events involving individual PSVs, occurring at a rate of 2.9-8.4×10(-4) events per generation. A consideration of the nature of nucleotide change and the ancestral state of each PSV showed that the conversion process was significantly biased towards the fixation of G or C nucleotides (GC-biased), and also towards the ancestral state. Determination of haplotypes by long-PCR allowed likely co-conversion of PSVs to be identified, and suggested that conversion tract lengths are large, with a mean of 2068 bp, and a maximum in excess of 9 kb. Despite the frequent formation of recombination intermediates implied by the rapid observed gene conversion activity, resolution via crossover is rare: only three inversions within P6 were detected in the sample. An analysis of chimpanzee and gorilla P6 orthologs showed that the ancestral state bias has existed in all three species, and comparison of human and chimpanzee sequences with the gorilla outgroup confirmed that GC bias of the conversion process has apparently been active in both the human and chimpanzee lineages.

Spatial and temporal variation in population genetic structure of wild Nile tilapia (Oreochromis niloticus) across Africa.

BACKGROUND: Reconstructing the evolutionary history of a species is challenging. It often depends not only on the past biogeographic and climatic events but also the contemporary and ecological factors, such as current connectivity and habitat heterogeneity. In fact, these factors might interact with each other and shape the current species distribution. However, to what extent the current population genetic structure reflects the past and the contemporary factors is largely unknown. Here we investigated spatio-temporal genetic structures of Nile tilapia (Oreochromis niloticus) populations, across their natural distribution in Africa. While its large biogeographic distribution can cause genetic differentiation at the paleo-biogeographic scales, its restricted dispersal capacity might induce a strong genetic structure at micro-geographic scales. RESULTS: Using nine microsatellite loci and 350 samples from ten natural populations, we found the highest genetic differentiation among the three ichthyofaunal provinces and regions (Ethiopian, Nilotic and Sudano-Sahelian) (R(ST) = 0.38 - 0.69). This result suggests the predominant effect of paleo-geographic events at macro-geographic scale. In addition, intermediate divergences were found between rivers and lakes within the regions, presumably reflecting relatively recent interruptions of gene flow between hydrographic basins (R(ST) = 0.24 - 0.32). The lowest differentiations were observed among connected populations within a basin (R(ST) = 0.015 in the Volta basin). Comparison of temporal sample series revealed subtle changes in the gene pools in a few generations (F = 0 - 0.053). The estimated effective population sizes were 23 - 143 and the estimated migration rate was moderate (m ~ 0.094 - 0.097) in the Volta populations. CONCLUSIONS: This study revealed clear hierarchical patterns of the population genetic structuring of O. niloticus in Africa. The effects of paleo-geographic and climatic events were predominant at macro-geographic scale, and the significant effect of geographic connectivity was detected at micro-geographic scale. The estimated effective population size, the moderate level of dispersal and the rapid temporal change in genetic composition might reflect a potential effect of life history strategy on population dynamics. This hypothesis deserves further investigation. The dynamic pattern revealed at micro-geographic and temporal scales appears important from a genetic resource management as well as from a biodiversity conservation point of view.

Population genetics of 17 Y-chromosomal STR loci in Yakutia.

Haplotype and allele frequencies of 17 Y-chromosomal short tandem repeat (Y-STR) markers in a population sample of 133 Yakut male volunteers from two regions: Central (n=41) and Western Yakutia (n=92) were determined using the AmpFlSTR Yfiler PCR Amplification Kit (Applied Biosystems). A total of 65 haplotypes were identified in the Yakut population, with 15 haplotypes in Central sample and 54 haplotypes in Western sample. Haplotype diversity values of 0.79 and 0.96, and average gene diversity values of 0.14 and 0.41 were calculated for Central and Western samples, respectively. The Fst distances between both our Yakut populations with other Russian, Siberian and Chinese populations were represented by MDS plot. The graphical view demonstrated close distances between most Yakut populations and differences with other Siberian populations.

A predominantly neolithic origin for European paternal lineages.

The relative contributions to modern European populations of Paleolithic hunter-gatherers and Neolithic farmers from the Near East have been intensely debated. Haplogroup R1b1b2 (R-M269) is the commonest European Y-chromosomal lineage, increasing in frequency from east to west, and carried by 110 million European men. Previous studies suggested a Paleolithic origin, but here we show that the geographical distribution of its microsatellite diversity is best explained by spread from a single source in the Near East via Anatolia during the Neolithic. Taken with evidence on the origins of other haplogroups, this indicates that most European Y chromosomes originate in the Neolithic expansion. This reinterpretation makes Europe a prime example of how technological and cultural change is linked with the expansion of a Y-chromosomal lineage, and the contrast of this pattern with that shown by maternally inherited mitochondrial DNA suggests a unique role for males in the transition.

Genetic diversity and the emergence of ethnic groups in Central Asia.

BACKGROUND: In this study, we used genetic data that we collected in Central Asia, in addition to data from the literature, to understand better the origins of Central Asian groups at a fine-grained scale, and to assess how ethnicity influences the shaping of genetic differences in the human species. We assess the levels of genetic differentiation between ethnic groups on one hand and between populations of the same ethnic group on the other hand with mitochondrial and Y-chromosomal data from several populations per ethnic group from the two major linguistic groups in Central Asia. RESULTS: Our results show that there are more differences between populations of the same ethnic group than between ethnic groups for the Y chromosome, whereas the opposite is observed for mtDNA in the Turkic group. This is not the case for Tajik populations belonging to the Indo-Iranian group where the mtDNA like the Y-chomosomal differentiation is also significant between populations within this ethnic group. Further, the Y-chromosomal analysis of genetic differentiation between populations belonging to the same ethnic group gives some estimation of the minimal age of these ethnic groups. This value is significantly higher than what is known from historical records for two of the groups and lends support to Barth's hypothesis by indicating that ethnicity, at least for these two groups, should be seen as a constructed social system maintaining genetic boundaries with other ethnic groups, rather than the outcome of common genetic ancestry CONCLUSION: Our analysis of uniparental markers highlights in Central Asia the differences between Turkic and Indo-Iranian populations in their sex-specific differentiation and shows good congruence with anthropological data.

Gene conversion between the X chromosome and the male-specific region of the Y chromosome at a translocation hotspot.

Outside the pseudoautosomal regions, the mammalian sex chromosomes are thought to have been genetically isolated for up to 350 million years. However, in humans pathogenic XY translocations occur in XY-homologous (gametologous) regions, causing sex-reversal and infertility. Gene conversion might accompany recombination intermediates that resolve without translocation and persist in the population. We resequenced X and Y copies of a translocation hotspot adjacent to the PRKX and PRKY genes and found evidence of historical exchange between the male-specific region of the human Y and the X in patchy flanking gene-conversion tracts on both chromosomes. The rate of X-to-Y conversion (per base per generation) is four to five orders of magnitude more rapid than the rate of Y-chromosomal base-substitution mutation, and given assumptions about the recombination history of the X locus, tract lengths have an overall average length of approximately 100 bp. Sequence exchange outside the pseudoautosomal regions could play a role in protecting the Y-linked copies of gametologous genes from degeneration.

Genetic structure and dynamics of a small introduced population: the pikeperch, Sander lucioperca, in the Rhône delta.

Genetic data on introduced populations may help us to understand how these species succeed in colonising new territories. The pikeperch is a predatory fish widely introduced in Europe and has at times been considered as an invasive species. However, little is known about the genetics of both native and introduced populations. In the present study, we surveyed an introduced pikeperch population from the Rhône River delta, a habitat that has been highly modified for agricultural purposes. Using six microsatellites, we genotyped 93 individuals distributed among four hydraulically connected water bodies: the Rhône River, an irrigation canal, a drainage canal and a brackish lagoon. Population isolation were revealed by significant genetic distances and bottleneck highlighted by population monitoring. However, values of allelic richness and unbiased expected heterozygosity observed in these populations were similar, or even higher, compare to 18 native populations from the Baltic Sea drainage. It may be explained by multiple introductions in the Rhône drainage but also by demographic strategy that would have facilitated population persistence in this fragmented habitat. Similarly, heterozygote deficits (revealed by F(IS) values) have been detected, but were also found in native populations suggesting that mating among relatives could also result from a mating behavior of the species, maybe reinforce here by the reduced carrying capacity of the artificial canals and their respective isolation. Despite harsh environmental conditions and suspected inbreeding, the pikeperch has successfully maintained viable populations in the Rhône delta. Our study suggests that one of the factors in this invasive success, apart from its ecology, could be the maintenance of a good level of genetic diversity in introduced pikeperch populations. This genetic diversity probably stem from both its popularity as game fish and food resource which led to numerous stocking and an increasing propagule pressure and the reproductive strategy of the species.

Genomic complexity of the Y-STR DYS19: inversions, deletions and founder lineages carrying duplications.

The Y-STR DYS19 is firmly established in the repertoire of Y-chromosomal markers used in forensic analysis yet is poorly understood at the molecular level, lying in a complex genomic environment and exhibiting null alleles, as well as duplications and occasional triplications in population samples. Here, we analyse three null alleles and 51 duplications and show that DYS19 can also be involved in inversion events, so that even its location within the short arm of the Y chromosome is uncertain. Deletion mapping in the three chromosomes carrying null alleles shows that their deletions are less than approximately 300 kb in size. Haplotypic analysis with binary markers shows that they belong to three different haplogroups and so represent independent events. In contrast, a collection of 51 DYS19 duplication chromosomes belong to only four haplogroups: two are singletons and may represent somatic mutation in lymphoblastoid cell lines, but two, in haplogroups G and C3c, represent founder lineages that have spread widely in Central Europe/West Asia and East Asia, respectively. Consideration of candidate mechanisms underlying both deletions and duplications provides no evidence for the involvement of non-allelic homologous recombination, and they are likely to represent sporadic events with low mutation rates. Understanding the basis and population distribution of these DYS19 alleles will aid in the utilisation and interpretation of profiles that contain them.

The genetic legacy of religious diversity and intolerance: paternal lineages of Christians, Jews, and Muslims in the Iberian Peninsula.

Most studies of European genetic diversity have focused on large-scale variation and interpretations based on events in prehistory, but migrations and invasions in historical times could also have had profound effects on the genetic landscape. The Iberian Peninsula provides a suitable region for examination of the demographic impact of such recent events, because its complex recent history has involved the long-term residence of two very different populations with distinct geographical origins and their own particular cultural and religious characteristics-North African Muslims and Sephardic Jews. To address this issue, we analyzed Y chromosome haplotypes, which provide the necessary phylogeographic resolution, in 1140 males from the Iberian Peninsula and Balearic Islands. Admixture analysis based on binary and Y-STR haplotypes indicates a high mean proportion of ancestry from North African (10.6%) and Sephardic Jewish (19.8%) sources. Despite alternative possible sources for lineages ascribed a Sephardic Jewish origin, these proportions attest to a high level of religious conversion (whether voluntary or enforced), driven by historical episodes of social and religious intolerance, that ultimately led to the integration of descendants. In agreement with the historical record, analysis of haplotype sharing and diversity within specific haplogroups suggests that the Sephardic Jewish component is the more ancient. The geographical distribution of North African ancestry in the peninsula does not reflect the initial colonization and subsequent withdrawal and is likely to result from later enforced population movement-more marked in some regions than in others-plus the effects of genetic drift.