scholarly journals Long runs of homozygosity are correlated with marriage preferences across global population samples

2021 ◽  
Author(s):  
Samali Anova Sahoo ◽  
Arslan A. Zaidi ◽  
Santosh Anagol ◽  
Iain Mathieson
Keyword(s):  
Genetic Variation ◽  
Demographic History ◽  
Global Scale ◽  
Detectable Effect ◽  
Human Genetic Variation ◽  
Runs Of Homozygosity ◽  
Expected Number ◽  
Cousin Marriage ◽  
Shared Ancestry ◽  
Global Population

AbstractChildren of consanguineous unions carry long runs of homozygosity (ROH) in their genomes, due to their parents’ recent shared ancestry. This increases the burden of recessive disease in populations with high levels of consanguinity and has been heavily studied in some groups. However, there has been little investigation of the broader effect of consanguinity on patterns of genetic variation on a global scale. Here, we collect published genetic data and information about marriage practices from 396 worldwide populations and show that preference for cousin marriage has a detectable effect on the distribution of long ROH in these samples, increasing the expected number of ROH longer than 10Mb by a factor of 1.5 (P=2.3 × 10−4). Variation in marriage practice and consequent rates of consanguinity is therefore an important aspect of demographic history for the purposes of modeling human genetic variation. However, marriage practices explain a relatively small proportion of the variation in ROH distribution and consequently the ability to predict marriage practices from population genetic samples (for example of ancient populations) is limited.

scholarly journals A comparison of worldwide phonemic and genetic variation in human populations

2015 ◽  
Vol 112 (5) ◽  
pp. 1265-1272 ◽  
Author(s):  
Nicole Creanza ◽  
Merritt Ruhlen ◽  
Trevor J. Pemberton ◽  
Noah A. Rosenberg ◽  
Marcus W. Feldman ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Demographic History ◽  
Horizontal Transmission ◽  
Geographic Distance ◽  
Global Scale ◽  
Human Populations ◽  
Isolated Populations ◽  
Human Dispersal ◽  
Genetic Sampling ◽  
Serial Founder Effect

Worldwide patterns of genetic variation are driven by human demographic history. Here, we test whether this demographic history has left similar signatures on phonemes—sound units that distinguish meaning between words in languages—to those it has left on genes. We analyze, jointly and in parallel, phoneme inventories from 2,082 worldwide languages and microsatellite polymorphisms from 246 worldwide populations. On a global scale, both genetic distance and phonemic distance between populations are significantly correlated with geographic distance. Geographically close language pairs share significantly more phonemes than distant language pairs, whether or not the languages are closely related. The regional geographic axes of greatest phonemic differentiation correspond to axes of genetic differentiation, suggesting that there is a relationship between human dispersal and linguistic variation. However, the geographic distribution of phoneme inventory sizes does not follow the predictions of a serial founder effect during human expansion out of Africa. Furthermore, although geographically isolated populations lose genetic diversity via genetic drift, phonemes are not subject to drift in the same way: within a given geographic radius, languages that are relatively isolated exhibit more variance in number of phonemes than languages with many neighbors. This finding suggests that relatively isolated languages are more susceptible to phonemic change than languages with many neighbors. Within a language family, phoneme evolution along genetic, geographic, or cognate-based linguistic trees predicts similar ancestral phoneme states to those predicted from ancient sources. More genetic sampling could further elucidate the relative roles of vertical and horizontal transmission in phoneme evolution.

Revitalizing Difference in the HapMap: Race and Contemporary Human Genetic Variation Research

2008 ◽  
Vol 36 (3) ◽  
pp. 471-477 ◽  
Author(s):  
Jennifer A. Hamilton
Keyword(s):  
Genetic Variation ◽  
Human Genome ◽  
Genetic Research ◽  
The United States ◽  
Genome Project ◽  
Human Genetic Variation ◽  
Early 21St Century ◽  
The Social ◽  
English Speaking ◽  
The Human Genome Project

In 2000, researchers from the Human Genome Project (HGP) proclaimed that the initial sequencing of the human genome definitively proved, among other things, that there was no genetic basis for race. The genetic fact that most humans were 99.9% the same at the level of their DNA was widely heralded and circulated in the English-speaking press, especially in the United States. This pronouncement seemed proof that long-term antiracist efforts to de-biologize race were legitimized by scientific findings. Yet, despite the seemingly widespread acceptance of the social construction of race, post-HGP genetic science has seen a substantial shift toward the use of race variables in genetic research and, according to a number of prominent scholars, is re-invoking the specter of earlier forms of racial science in some rather discomfiting ways. During the past seven years, the main thrust of human genetic research, especially in the realm of biomedicine, has shifted from a concern with the 99.9% of the shared genome — what is thought to make humans alike — towards an explicit focus on the 0.1% that constitutes human genetic variation. Here I briefly explore some of the potential implications of the conceptualization and practice of early 21st century genetic variation research, especially as it relates to questions of race.

GENETIC DIVERSITY

PEDIATRICS ◽  
1977 ◽  
Vol 59 (3) ◽  
pp. 432-432
Author(s):  
R. C. Lewontin ◽  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Skin Color ◽  
Human Genetic Variation ◽  
Human Species

Only about 7% of all human genetic diversity is between major races. It would appear then that the superficial characters of skin color, hair form, lip, nose, and eye shape that we use to distinguish human races are atypical and do not represent the mode of human genetic variation. The taxonomic division of the human species into races places a completely disproportionate emphasis on a very small fraction of total human genetic diversity.

An overview of human genetic variation

2018 ◽  
pp. 361-396 ◽  
Author(s):  
Tom Strachan ◽  
Andrew P Read
Keyword(s):  
Genetic Variation ◽  
Human Genetic Variation

scholarly journals Climatic Refugia and Geographical Isolation Contribute to the Speciation and Genetic Divergence in Himalayan-Hengduan Tree Peonies (Paeonia delavayi and Paeonia ludlowii)

2021 ◽  
Vol 11 ◽  
Author(s):  
Yu-Juan Zhao ◽  
Gen-Shen Yin ◽  
Yue-Zhi Pan ◽  
Bo Tian ◽  
Xun Gong
Keyword(s):  
Genetic Variation ◽  
Late Quaternary ◽  
Demographic History ◽  
Nuclear Gene ◽  
Genetic Distances ◽  
Population Divergence ◽  
Widespread Species ◽  
Isolation With Migration ◽  
Isolation By Environment ◽  
Paeonia Delavayi

Himalaya and Hengduan Mountains (HHM) is a biodiversity hotspot, and very rich in endemic species. Previous phylogeographical studies proposed different hypotheses (vicariance and climate-driven speciation) in explaining diversification and the observed pattern of extant biodiversity, but it is likely that taxa are forming in this area in species-specific ways. Here, we reexplored the phylogenetic relationship and tested the corresponding hypotheses within Paeonia subsect. Delavayanae composed of one widespread species (Paeonia delavayi) and the other geographically confined species (Paeonia ludlowii). We gathered genetic variation data at three chloroplast DNA fragments and one nuclear gene from 335 individuals of 34 populations sampled from HHM. We performed a combination of population genetic summary statistics, isolation-with-migration divergence models, isolation by environment, and demographic history analyses. We found evidence for the current taxonomic treatment that P. ludlowii and P. delavayi are two different species with significant genetic differentiation. The significant isolation by environment was revealed within all sampled populations but genetic distances only explained by geographical distances within P. delavayi populations. The results of population divergence models and demographic history analyses indicated a progenitor–derivative relationship and the Late Quaternary divergence without gene flow between them. The coalescence of all sampled cpDNA haplotypes could date to the Late Miocene, and P. delavayi populations probably underwent a severe bottleneck in population size during the last glacial period. Genetic variation in Paeonia subsect. Delavayanae is associated with geographical and environmental distances. These findings point to the importance of geological and climatic changes as causes of the speciation event and lineage diversification within Paeonia subsect. Delavayanae.

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