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Evidence for Very Recent Positive Selection in Mongolians
Kazuhiro Nakayama1, Jun Ohashi2, Kazuhisa Watanabe1
1Division of Human Genetics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan.
Molecular Biology and Evolution
|April 27, 2017
Summary
Genetic analysis reveals recent positive selection in Mongolians, linked to adaptations in energy metabolism and reproduction. This finding sheds light on human evolutionary responses to environmental changes.
Area of Science:
- Human Genetics
- Population Genetics
- Evolutionary Biology
Background:
- The Mongol Empire's expansion was facilitated by nomadic pastoralism in Inner Asia's challenging environments.
- Understanding genetic adaptations in Mongolians can illuminate their historical success and human evolution.
Purpose of the Study:
- To investigate genetic adaptations in present-day Mongolian populations.
- To identify signatures of population-specific positive selection in the Mongolian genome.
Main Methods:
- Genotyping of 2.4 million single nucleotide polymorphisms (SNPs) in 96 unrelated Mongolian individuals.
- Genome-wide scans for positive selection.
- Approximate Bayesian computation for allele age estimation.
- Association analysis with adiposity traits and enhancer activity assays.
Main Results:
- Identified Mongolian-specific positive selection signatures at chromosomal region 3p12.1.
- The top SNP, rs117799927, showed a derived allele frequency of 0.247 in Mongolians, significantly higher than worldwide populations.
- The rs117799927 G allele emerged approximately 50 generations ago, coinciding with the Late Antique Little Ice Age.
- rs117799927 is associated with adiposity traits and exhibits allelic differences in enhancer activity.
Conclusions:
- Recent positive selection in Mongolians at 3p12.1 is linked to adaptation in energy metabolism.
- This study provides evidence for recent adaptive evolution in Homo sapiens.
- Genes in the 3p12.1 region play a role in human adaptive evolution.
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