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: Two probes specific for the DEFB2L region spanning chr8:8068951–8069850 and chr8:8072076–8073004 were generated by PCR from rhesus macaque genomic DNA and used to probe Segment 1 CHORI-250 BAC library filters (BACPAC Resources Center). In total, 21 positive clones were identified, of which six were selected for further analysis. BAC DNA was extracted from growing Escherichia coli cultures using cesium chloride ultracentrifugation, and end sequences generated using T7 and SP6 sequencing primers. Fluorescent in situ hybridization (FISH) with BAC 47B11 shows the main site on the distal end of the short arm of chromosome 8 (fig. 2C and D) with secondary and some dispersed signal due to repetitive elements contained within the BAC, whereas the probe for DEFB2L showed a signal only on chromosome 8. At interphase, one or two variably condensed domains are visible with chromosome 8 paint with the DEFB2L probe at the outside of the domain orientated to the interior of the nucleus (fig. 2F and G).
Affiliation: Department of Genetics, University of Leicester, United Kingdom.