title: The amelogenin loci span an ancient pseudoautosomal boundary in diverse mammalian species.
abstract: The mammalian amelogenin (AMEL) genes are found on both the X and Y chromosomes (gametologous). Comparison of the genomic AMEL sequences in five primates and three other mammals reveals that the 5' portion of the gametologous AMEL loci began to differentiate in the common ancestor of extant mammals, whereas the 3' portion differentiated independently within species of different mammals. The boundary is marked by a transposon insertion in intron 2 and is shared by all species examined. In addition, 540-kb DNA sequences from the short arm of the human X chromosome are aligned with their Y gametologous sequences. The pattern and extent of sequence differences in the 5' portion of the AMEL loci extend to a proximal region that contains the ZFX locus, and those in the 3' portion extend all the way down to the pseudoautosomal boundary (PAB)1. We concluded that the AMEL locus spans an ancient PAB, and that both the ancient and present PABs were determined by chance events during the evolution of mammals and primates. Sex chromosome differentiation likely took place in a region that contains the male-determining loci by suppressing homologous recombination.
authors.affiliation: Department of Biosystems Science, Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa 240-0193, Japan.
authors.forename: Mineyo
authors.initials: M
authors.lastname: Iwase
authors.forename: Yoko
authors.initials: Y
authors.lastname: Satta
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Hirai
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Hirai
authors.forename: Hirotami
authors.initials: H
authors.lastname: Imai
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Takahata
mesh_terms: D053523:Amelogenin; D000818:Animals; D002874:Chromosome Mapping; D003746:Dental Enamel Proteins / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D010802:Phylogeny; D013045:Species Specificity; D014960:X Chromosome; D014998:Y Chromosome
chemical_list: D053523:Amelogenin; D003746:Dental Enamel Proteins