Evidence of convergent evolution in humans and macaques supports an adaptive role for copy number variation of the β-defensin-2 gene.
Bottom Line: Remarkably, we found that the structure of the CNV is different between primates, with distinct mutational origins and CNV boundaries defined by retroviral long terminal repeat elements.In addition, the rhesus macaque gene has been subject to divergent positive selection at the amino acid level following its initial duplication event between 3 and 9.5 Ma, suggesting adaptation of this gene as the macaque successfully colonized novel environments outside Africa.Therefore, the molecular phenotype of β-defensin-2 CNV has undergone convergent evolution, and this gene shows evidence of adaptation at the amino acid level in rhesus macaques.
Affiliation: Department of Genetics, University of Leicester, United Kingdom.Show MeSH
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Mentions: In humans, analysis of both assembled regions shows that at the boundary between the β-defensin CNV and more complex flanking regions is a section of a long terminal repeat (LTR) (LTR5A) of the ape-specific endogenous retrovirus family ERVK (Repeatmasker database [Smit et al. 2010], http://www.repeatmasker.org, last accessed October 29, 2014), organized antiparallel to each side of the CNV region (fig. 4). The antiparallel arrangement of the LTR reflects the antiparallel arrangement of the complex segmental duplication-rich region flanking the CNV boundaries, a region which contains olfactory receptor genes. This arrangement suggests that this region is closely tied to the polymorphic recurrent inversion of 8p23.1, which is known to involve the REPP and REPD regions (Giglio et al. 2001; Salm et al. 2012).Fig. 4.—
Affiliation: Department of Genetics, University of Leicester, United Kingdom.