title: Multicopy gene family evolution on primate Y chromosomes.
abstract: BACKGROUND
  The primate Y chromosome is distinguished by a lack of inter-chromosomal recombination along most of its length, extensive gene loss, and a prevalence of repetitive elements. A group of genes on the male-specific portion of the Y chromosome known as the "ampliconic genes" are present in multiple copies that are sometimes part of palindromes, and that undergo a form of intra-chromosomal recombination called gene conversion, wherein the nucleotides of one copy are homogenized by those of another. With the aim of further understanding gene family evolution of these genes, we collected nucleotide sequence and gene copy number information for several species of papionin monkey. We then tested for evidence of gene conversion, and developed a novel statistical framework to evaluate alternative models of gene family evolution using our data combined with other information from a human, a chimpanzee, and a rhesus macaque.
  
  
  RESULTS
  Our results (i) recovered evidence for several novel examples of gene conversion in papionin monkeys and indicate that (ii) ampliconic gene families evolve faster than autosomal gene families and than single-copy genes on the Y chromosome and that (iii) Y-linked singleton and autosomal gene families evolved faster in humans and chimps than they do in the other Old World Monkey lineages we studied.
  
  
  CONCLUSIONS
  Rapid evolution of ampliconic genes cannot be attributed solely to residence on the Y chromosome, nor to variation between primate lineages in the rate of gene family evolution. Instead other factors, such as natural selection and gene conversion, appear to play a role in driving temporal and genomic evolutionary heterogeneity in primate gene families.
authors.affiliation: Biology Department, McMaster University, 1280 Main Street West, Hamilton, L8S 4K1, Canada. ghenua@mcmaster.ca.
authors.forename: Ana-Hermina
authors.initials: AH
authors.lastname: Ghenu
authors.affiliation: Biology Department, McMaster University, 1280 Main Street West, Hamilton, L8S 4K1, Canada.|Department of Mathematics & Statistics, McMaster University, 1280 Main Street West, Hamilton, L8S 4K1, Canada.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Bolker
authors.affiliation: Department of Ecology, Evolution, and Environmental Biology, Columbia University, 10th Floor Schermerhorn Extension, New York, 10027, USA.
authors.forename: Don J
authors.initials: DJ
authors.lastname: Melnick
authors.affiliation: Biology Department, McMaster University, 1280 Main Street West, Hamilton, L8S 4K1, Canada. evansb@mcmaster.ca.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Evans
mesh_terms: D000818:Animals; D001483:Base Sequence; D041322:Chromosomes, Human, Y / Q000235:genetics*; D019143:Evolution, Molecular; D005785:Gene Conversion; D018628:Gene Dosage; D006801:Humans; D008253:Macaca mulatta / Q000235:genetics; D008297:Male; D048528:Mandrillus / Q000235:genetics; D008957:Models, Genetic; D005810:Multigene Family; D002679:Pan troglodytes / Q000235:genetics; D048530:Papio anubis / Q000235:genetics; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014998:Y Chromosome / Q000235:genetics*