Apportioning archaic variants among modern populations.

Area of Science:

• Population Genetics
• Human Evolution
• Paleogenomics

Background:

• Understanding human genetic diversity and demographic history relies on analyzing genetic variation within and between populations.
• Archaic ancestry distribution in modern humans offers insights into interactions between Homo sapiens and archaic hominins like Neanderthals.
• Interactions between modern and archaic humans are complex, influenced by genetic drift, population bottlenecks, and gene flow.

Purpose of the Study:

• To investigate the distribution patterns of archaic variation, specifically Neanderthal ancestry, across Eurasian populations.
• To explore how demographic history and admixture events have shaped the presence of archaic genetic material in modern humans.
• To compare Neanderthal ancestry levels between different Eurasian groups and contrast individual-level versus population-level findings.

Main Methods:

• Analysis of archaic ancestry coverage at both individual and population levels in Eurasian populations.
• Comparison of population-unique archaic alleles and single nucleotide polymorphisms (SNPs) with archaic alleles.
• Utilizing simulated models to interpret observed patterns of archaic admixture.

Main Results:

• South Asian populations exhibit nearly double the number of population-unique archaic alleles compared to Europeans and East Asians.
• While East Asians have more Neanderthal ancestry per individual, Europeans show a higher number of Neanderthal-associated SNPs across the population.
• Observed patterns suggest distinct demographic histories and multiple admixture events between modern humans and Neanderthals in different Eurasian groups.

Conclusions:

• Archaic ancestry distribution varies significantly across Eurasian populations, indicating differing demographic trajectories and admixture histories.
• The complex Neanderthal ancestry patterns in Europeans and East Asians support models involving multiple admixture events.
• This research contributes to understanding the intricate evolutionary relationship between modern humans and archaic hominins.