scholarly journals Tracking human population structure through time from whole genome sequences

2019 ◽  
Author(s):  
Ke Wang ◽  
Iain Mathieson ◽  
Jared O’Connell ◽  
Stephan Schiffels
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Demographic History ◽  
Time Dependent ◽  
Human Populations ◽  
Whole Genome ◽  
Genome Sequences ◽  
Migration Model ◽  
Novel Approach ◽  
Different Populations

AbstractThe genetic diversity of humans, like many species, has been shaped by a complex pattern of population separations followed by isolation and subsequent admixture. This pattern, reaching at least as far back as the appearance of our species in the paleontological record, has left its traces in our genomes. Reconstructing a population’s history from these traces is a challenging problem. Here we present a novel approach based on the Multiple Sequentially Markovian Coalescent (MSMC) to analyse the population separation history. Our approach, called MSMC-IM, uses an improved implementation of the MSMC (MSMC2) to estimate coalescence rates within and across pairs of populations, and then fits a continuous Isolation-Migration model to these rates to obtain a time-dependent estimate of gene flow. We show, using simulations, that our method can identify complex demographic scenarios involving post-split admixture or archaic introgression. We apply MSMC-IM to whole genome sequences from 15 worldwide populations, tracking the process of human genetic diversification. We detect traces of extremely deep ancestry between some African populations, with around 1% of ancestry dating to divergences older than a million years ago.Author SummaryHuman demographic history is reflected in specific patterns of shared mutations between the genomes from different populations. Here we aim to unravel this pattern to infer population structure through time with a new approach, called MSMC-IM. Based on estimates of coalescence rates within and across populations, MSMC-IM fits a time-dependent migration model to the pairwise rate of coalescences. We implemented this approach as an extension to existing software (MSMC2), and tested it with simulations exhibiting different histories of admixture and gene flow. We then applied it to the genomes from 15 worldwide populations to reveal their pairwise separation history ranging from a few thousand up to several million years ago. Among other results, we find evidence for remarkably deep population structure in some African population pairs, suggesting that deep ancestry dating to one million years ago and older is still present in human populations in small amounts today.

scholarly journals Analysis of whole-genome re-sequencing data of ducks reveals a diverse demographic history and extensive gene flow between Southeast/South Asian and Chinese populations

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Fan Jiang ◽  
Ruiyi Lin ◽  
Changyi Xiao ◽  
Tanghui Xie ◽  
Yaoxin Jiang ◽  
...  
Keyword(s):  
Gene Flow ◽  
South Asia ◽  
South Asian ◽  
Demographic History ◽  
Nervous System Development ◽  
Chromosome 1 ◽  
Whole Genome ◽  
Chinese Populations ◽  
Asian Populations ◽  
History Of

Abstract Background The most prolific duck genetic resource in the world is located in Southeast/South Asia but little is known about the domestication and complex histories of these duck populations. Results Based on whole-genome resequencing data of 78 ducks (Anas platyrhynchos) and 31 published whole-genome duck sequences, we detected three geographic distinct genetic groups, including local Chinese, wild, and local Southeast/South Asian populations. We inferred the demographic history of these duck populations with different geographical distributions and found that the Chinese and Southeast/South Asian ducks shared similar demographic features. The Chinese domestic ducks experienced the strongest population bottleneck caused by domestication and the last glacial maximum (LGM) period, whereas the Chinese wild ducks experienced a relatively weak bottleneck caused by domestication only. Furthermore, the bottleneck was more severe in the local Southeast/South Asian populations than in the local Chinese populations, which resulted in a smaller effective population size for the former (7100–11,900). We show that extensive gene flow has occurred between the Southeast/South Asian and Chinese populations, and between the Southeast Asian and South Asian populations. Prolonged gene flow was detected between the Guangxi population from China and its neighboring Southeast/South Asian populations. In addition, based on multiple statistical approaches, we identified a genomic region that included three genes (PNPLA8, THAP5, and DNAJB9) on duck chromosome 1 with a high probability of gene flow between the Guangxi and Southeast/South Asian populations. Finally, we detected strong signatures of selection in genes that are involved in signaling pathways of the nervous system development (e.g., ADCYAP1R1 and PDC) and in genes that are associated with morphological traits such as cell growth (e.g., IGF1R). Conclusions Our findings provide valuable information for a better understanding of the domestication and demographic history of the duck, and of the gene flow between local duck populations from Southeast/South Asia and China.

scholarly journals Whole genome sequences are required to fully resolve the linkage disequilibrium structure of human populations

BMC Genomics ◽  
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Reuben J. Pengelly ◽  
William Tapper ◽  
Jane Gibson ◽  
Marcin Knut ◽  
Rick Tearle ◽  
...  
Keyword(s):  
Linkage Disequilibrium ◽  
Human Populations ◽  
Whole Genome ◽  
Linkage Disequilibrium Structure ◽  
Genome Sequences

scholarly journals Insights into human genetic variation and population history from 929 diverse genomes

2019 ◽  
Author(s):  
Anders Bergström ◽  
Shane A. McCarthy ◽  
Ruoyun Hui ◽  
Mohamed A. Almarri ◽  
Qasim Ayub ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Central Africa ◽  
Population History ◽  
Human Populations ◽  
Genome Sequences ◽  
High Coverage ◽  
Geographical Regions ◽  
History Of ◽  
Different Populations ◽  
Source Populations

AbstractGenome sequences from diverse human groups are needed to understand the structure of genetic variation in our species and the history of, and relationships between, different populations. We present 929 high-coverage genome sequences from 54 diverse human populations, 26 of which are physically phased using linked-read sequencing. Analyses of these genomes reveal an excess of previously undocumented private genetic variation in southern and central Africa and in Oceania and the Americas, but an absence of fixed, private variants between major geographical regions. We also find deep and gradual population separations within Africa, contrasting population size histories between hunter-gatherer and agriculturalist groups in the last 10,000 years, a potentially major population growth episode after the peopling of the Americas, and a contrast between single Neanderthal but multiple Denisovan source populations contributing to present-day human populations. We also demonstrate benefits to the study of population relationships of genome sequences over ascertained array genotypes. These genome sequences are freely available as a resource with no access or analysis restrictions.

scholarly journals Detection of stable community structures within gut microbiota co-occurrence networks from different human populations

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4303 ◽  
Author(s):  
Matthew A. Jackson ◽  
Marc Jan Bonder ◽  
Zhana Kuncheva ◽  
Jonas Zierer ◽  
Jingyuan Fu ◽  
...  
Keyword(s):  
Community Structure ◽  
Gut Microbiota ◽  
Human Populations ◽  
Specific Interactions ◽  
Diverse Populations ◽  
Community Structures ◽  
Operational Taxonomic Units ◽  
Novel Approach ◽  
Different Populations ◽  
Multiple Samples

Microbes in the gut microbiome form sub-communities based on shared niche specialisations and specific interactions between individual taxa. The inter-microbial relationships that define these communities can be inferred from the co-occurrence of taxa across multiple samples. Here, we present an approach to identify comparable communities within different gut microbiota co-occurrence networks, and demonstrate its use by comparing the gut microbiota community structures of three geographically diverse populations. We combine gut microbiota profiles from 2,764 British, 1,023 Dutch, and 639 Israeli individuals, derive co-occurrence networks between their operational taxonomic units, and detect comparable communities within them. Comparing populations we find that community structure is significantly more similar between datasets than expected by chance. Mapping communities across the datasets, we also show that communities can have similar associations to host phenotypes in different populations. This study shows that the community structure within the gut microbiota is stable across populations, and describes a novel approach that facilitates comparative community-centric microbiome analyses.

scholarly journals Insights into platypus population structure and history from whole-genome sequencing

2017 ◽  
Author(s):  
Hilary C. Martin ◽  
Elizabeth M. Batty ◽  
Julie Hussin ◽  
Portia Westall ◽  
Tasman Daish ◽  
...  
Keyword(s):  
Population Structure ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
De Novo ◽  
Demographic History ◽  
Population Decline ◽  
Egg Laying ◽  
Whole Genome ◽  
Data Set ◽  
Important Species

AbstractThe platypus is an egg-laying mammal which, alongside the echidna, occupies a unique place in the mammalian phylogenetic tree. Despite widespread interest in its unusual biology, little is known about its population structure or recent evolutionary history. To provide new insights into the dispersal and demographic history of this iconic species, we sequenced the genomes of 57 platypuses from across the whole species range in eastern mainland Australia and Tasmania. Using a highly-improved reference genome, we called over 6.7M SNPs, providing an informative genetic data set for population analyses. Our results show very strong population structure in the platypus, with our sampling locations corresponding to discrete groupings between which there is no evidence for recent gene flow. Genome-wide data allowed us to establish that 28 of the 57 sampled individuals had at least a third-degree relative amongst other samples from the same river, often taken at different times. Taking advantage of a sampled family quartet, we estimated the de novo mutation rate in the platypus at 7.0×10−9/bp/generation (95% CI 4.1×10−9 − 1.2×10−8/bp/generation). We estimated effective population sizes of ancestral populations and haplotype sharing between current groupings, and found evidence for bottlenecks and long-term population decline in multiple regions, and early divergence between populations in different regions. This study demonstrates the power of whole-genome sequencing for studying natural populations of an evolutionarily important species.

scholarly journals Whole genome sequence analyses of Western Central African Pygmy hunter-gatherers reveal a complex demographic history and identify candidate genes under positive natural selection

2015 ◽  
Author(s):  
PingHsun Hsieh ◽  
Krishna R Veeramah ◽  
Joseph Lachance ◽  
Sarah A Tishkoff ◽  
Jeffrey D Wall ◽  
...  
Keyword(s):  
Gene Flow ◽  
Natural Selection ◽  
Muscle Development ◽  
Demographic History ◽  
Single Pulse ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Anatomically Modern Humans ◽  
History Of ◽  
African Pygmies

African Pygmies practicing a mobile hunter-gatherer lifestyle are phenotypically and genetically diverged from other anatomically modern humans, and they likely experienced strong selective pressures due to their unique lifestyle in the Central African rainforest. To identify genomic targets of adaptation, we sequenced the genomes of four Biaka Pygmies from the Central African Republic and jointly analyzed these data with the genome sequences of three Baka Pygmies from Cameroon and nine Yoruba famers. To account for the complex demographic history of these populations that includes both isolation and gene flow, we fit models using the joint allele frequency spectrum and validated them using independent approaches. Our two best-fit models both suggest ancient divergence between the ancestors of the farmers and Pygmies, 90,000 or 150,000 years ago. We also find that bi-directional asymmetric gene-flow is statistically better supported than a single pulse of unidirectional gene flow from farmers to Pygmies, as previously suggested. We then applied complementary statistics to scan the genome for evidence of selective sweeps and polygenic selection. We found that conventional statistical outlier approaches were biased toward identifying candidates in regions of high mutation or low recombination rate. To avoid this bias, we assigned P-values for candidates using whole-genome simulations incorporating demography and variation in both recombination and mutation rates. We found that genes and gene sets involved in muscle development, bone synthesis, immunity, reproduction, cell signaling and development, and energy metabolism are likely to be targets of positive natural selection in Western African Pygmies or their recent ancestors.

scholarly journals Tracking human population structure through time from whole genome sequences

PLoS Genetics ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. e1008552 ◽  
Author(s):  
Ke Wang ◽  
Iain Mathieson ◽  
Jared O’Connell ◽  
Stephan Schiffels
Keyword(s):  
Population Structure ◽  
Human Population ◽  
Whole Genome ◽  
Genome Sequences

Whole-genome sequences shed light onto the demographic history and contemporary genetic erosion of free-ranging jaguar (Panthera onca) populations

2021 ◽  
Author(s):  
Gustavo P. Lorenzana ◽  
Henrique V. Figueiró ◽  
Christopher B. Kaelin ◽  
Gregory S. Barsh ◽  
Jeremy Johnson ◽  
...  
Keyword(s):  
Demographic History ◽  
Genetic Erosion ◽  
Whole Genome ◽  
Panthera Onca ◽  
Genome Sequences ◽  
Free Ranging ◽  
Shed Light

scholarly journals Inferring number of populations and changes in connectivity under the n-island model

Heredity ◽  
2021 ◽  
Author(s):  
Armando Arredondo ◽  
Beatriz Mourato ◽  
Khoa Nguyen ◽  
Simon Boitard ◽  
Willy Rodríguez ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Population Size ◽  
Demographic History ◽  
Simulated Data ◽  
Fixed Number ◽  
Ancestral Population ◽  
Demographic Model ◽  
History Of ◽  
Time Periods

AbstractInferring the demographic history of species is one of the greatest challenges in populations genetics. This history is often represented as a history of size changes, ignoring population structure. Alternatively, when structure is assumed, it is defined a priori as a population tree and not inferred. Here we propose a framework based on the IICR (Inverse Instantaneous Coalescence Rate). The IICR can be estimated for a single diploid individual using the PSMC method of Li and Durbin (2011). For an isolated panmictic population, the IICR matches the population size history, and this is how the PSMC outputs are generally interpreted. However, it is increasingly acknowledged that the IICR is a function of the demographic model and sampling scheme with limited connection to population size changes. Our method fits observed IICR curves of diploid individuals with IICR curves obtained under piecewise stationary symmetrical island models. In our models we assume a fixed number of time periods during which gene flow is constant, but gene flow is allowed to change between time periods. We infer the number of islands, their sizes, the periods at which connectivity changes and the corresponding rates of connectivity. Validation with simulated data showed that the method can accurately recover most of the scenario parameters. Our application to a set of five human PSMCs yielded demographic histories that are in agreement with previous studies using similar methods and with recent research suggesting ancient human structure. They are in contrast with the view of human evolution consisting of one ancestral population branching into three large continental and panmictic populations with varying degrees of connectivity and no population structure within each continent.

scholarly journals Complex population structure of the Atlantic puffin revealed by whole genome analyses

2020 ◽  
Author(s):  
Oliver Kersten ◽  
Bastiaan Star ◽  
Deborah M. Leigh ◽  
Tycho Anker-Nilssen ◽  
Hallvard Strøm ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Isolation By Distance ◽  
Spatial Scales ◽  
Secondary Contact ◽  
Whole Genome ◽  
Genome Data ◽  
Complex Population ◽  
Genome Analyses ◽  
Atlantic Puffin

AbstractThe factors underlying gene flow and genomic population structure in vagile seabirds are notoriously difficult to understand due to their complex ecology with diverse dispersal barriers and extensive periods at sea. Yet, such understanding is vital for conservation management of seabirds that are globally declining at alarming rates. Here, we elucidate the population structure of the Atlantic puffin (Fratercula arctica) by assembling its reference genome and analyzing genome-wide resequencing data of 72 individuals from 12 colonies. We identify four large, genetically distinct clusters, observe isolation-by-distance between colonies within these clusters, and obtain evidence for a secondary contact zone. These observations disagree with the current taxonomy, and show that a complex set of contemporary biotic factors impede gene flow over different spatial scales. Our results highlight the power of whole genome data to reveal unexpected population structure in vagile marine seabirds and its value for seabird taxonomy, evolution and conservation.

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