Detecting adaptive changes in gene copy number distribution accompanying the human out-of-Africa expansion

Genes with multiple copies are likely to be maintained by stabilizing selection, which puts a bound to unlimited expansion of copy number. We designed a model in which copy number variation is generated by unequal recombination, which fits well with several genes surveyed in three human populations. Based on this theoretical model and computer simulations, we were interested in determining whether the gene copy number distribution in the derived European and Asian populations can be explained by a purely demographic scenario or whether shifts in the distribution are signatures of adaptation. Although the copy number distribution in most of the analyzed gene clusters can be explained by a bottleneck, such as in the out-of-Africa expansion of Homo sapiens 60–10 kyrs ago, we identified several candidate genes, such as AMY1A and PGA3 , whose copy numbers are likely to differ among African, Asian, and European populations. Traces of human evolutionary history in gene copy numbers Gene copy number variation can influence evolution and adaptation. This study uses modeling and simulations to investigate these forces’ impact on CNV in human populations. The method combines real data analysis with simulations of human population history and genetic evolution, highlighting the importance of both historical events and survival pressures in shaping gene copy numbers. The results suggest that changes in gene copy numbers across different populations can not be fully explained by population history alone, implying that adaptive changes in survival pressures also play a key role. Specifically, genes related to diet and immune response show significant variations, suggesting a possible link to dietary habits and disease resistance. The study concludes that both population shifts and natural selection have influenced human genetic diversity, with survival changes contributing significantly to the observed variations in gene copy numbers. This summary was initially drafted using artificial intelligence, then revised and fact-checked by the author.