Institut de Biologia Evolutiva (UPF-CSIC), Universitat Pompeu Fabra, Barcelona, Catalonia, Spain.
Bioinformatics Studies, ESCI-UPF, Barcelona, Spain.
Genome Biol Evol. 2018 Apr 1;10(4):1132-1138. doi: 10.1093/gbe/evy077.
During the demographic history of the Pan clade, there has been gene-flow between species, likely >200,000 years ago. Bonobo haplotypes in three subspecies of chimpanzee have been identified to be segregating in modern-day chimpanzee populations, suggesting that these haplotypes, with increased differentiation, may be a target of natural selection. Here, we investigate signatures of adaptive introgression within the bonobo-like haplotypes in chimpanzees using site frequency spectrum-based tests. We find evidence for subspecies-specific adaptations in introgressed regions involved with male reproduction in central chimpanzees, the immune system in eastern chimpanzees, female reproduction and the nervous system in Nigeria-Cameroon chimpanzees. Furthermore, our results indicate signatures of balancing selection in some of the putatively introgressed regions. This might be the product of long-term balancing selection resulting in a similar genomic signature as introgression, or possibly balancing selection acting on alleles reintroduced through gene flow.
在 Pan 进化枝的人口历史中，物种间发生了基因流动，可能发生在 20 多万年前。在三种黑猩猩亚种的黑猩猩中发现了倭黑猩猩单倍型，这些单倍型在现代黑猩猩群体中发生了分离，这表明这些单倍型具有更高的分化程度，可能是自然选择的目标。在这里，我们使用基于位点频率谱的测试，研究了黑猩猩中类似倭黑猩猩的单倍型内适应性渐渗的特征。我们发现了在中部黑猩猩的雄性生殖、东部黑猩猩的免疫系统、尼日利亚-喀麦隆黑猩猩的雌性生殖和神经系统中，与渐渗有关的区域存在亚种特异性适应的证据。此外，我们的结果表明，在一些推测的渐渗区域存在平衡选择的特征。这可能是长期平衡选择的结果，导致了与渐渗相似的基因组特征，或者可能是平衡选择作用于通过基因流重新引入的等位基因。
