title: The cryptic Y-autosome translocation in the small Indian mongoose, Herpestes auropunctatus, revealed by molecular cytogenetic approaches.
abstract: In initial studies of the eutherian small Indian mongoose (Herpestes auropunctatus), the Y chromosome could not be identified in somatic cells. The male chromosome number is uniquely odd, 2n = 35, whereas that of females is 2n = 36. Previous reports indicated that this unique karyotype resulted from a translocation of the ancestral Y chromosome to an autosome. However, it has been difficult to identify the chromosomes that harbor the translocated Y chromosomal segment because it is an extremely small euchromatic region. Using a Southern blot analysis, we detected four conserved Y-linked genes, SRY, EIF2S3Y, KDM5D, and ZFY, in the male genome. We cloned homologues of these genes and determined their sequences, which showed high homology to genes in two carnivore species, cat and dog. To unambiguously identify the Y-bearing autosome, we performed immunostaining of pachytene spermatocytes using antibodies against SYCP3, γH2AX, and the centromere. We observed trivalent chromosomes, and the associations between the distal ends of the chromosomes were consistent with those of Y and X1 chromosomes. The centromere of the Y chromosome was located on the ancestral Y chromosomal segment. We mapped the complementary DNA (cDNA) clones of these genes to the male chromosomes using fluorescence in situ hybridization (FISH), and the linear localization of all genes was confirmed by two-colored FISH. These Y-linked genes were localized to the proximal region of the long arm of a single telomeric chromosome, and we successfully identified the chromosome harboring the ancestral Y chromosomal segment.
authors.affiliation: Department of Human Genetics, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Murata
authors.affiliation: Graduate School of Life Science, Hokkaido University, North 10, West 8, Kita-ku, Sapporo, 060-0810, Japan.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Sawaya
authors.affiliation: Yambaru Wildlife Conservation Center, Ministry of the Environment, 263-1 Hiji, Kunigami-son, Kunigami-gun, Okinawa, 905-1413, Japan.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Nakata
authors.affiliation: Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Yamada
authors.affiliation: Department of Human Genetics, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: Issei
authors.initials: I
authors.lastname: Imoto
authors.affiliation: Laboratory of Animal Cytogenetics, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, Hokkaido, 060-0810, Japan. asatok@sci.hokudai.ac.jp.
authors.forename: Asato
authors.initials: A
authors.lastname: Kuroiwa
mesh_terms: D000818:Animals; D001483:Base Sequence; D002415:Cats; D002478:Cells, Cultured; D002503:Centromere / Q000502:physiology; D003001:Cloning, Molecular; D004285:Dogs; D050173:Genes, Y-Linked / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics*; D008988:Herpestidae / Q000235:genetics*; D056466:Histone Demethylases / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence / Q000662:veterinary*; D059785:Karyotype; D051741:Kruppel-Like Transcription Factors / Q000235:genetics; D008297:Male; D017422:Sequence Analysis, DNA; D051876:Sex-Determining Region Y Protein / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D014178:Translocation, Genetic; D014998:Y Chromosome / Q000235:genetics*
chemical_list: D005819:Genetic Markers; D051741:Kruppel-Like Transcription Factors; D051876:Sex-Determining Region Y Protein; D014157:Transcription Factors; D056466:Histone Demethylases
keywords: Chromosome evolution; Fluorescence in situ hybridization; Meiosis; Y chromosome