title: Extraordinary Diversity in the Origins of Sex Chromosomes in Anurans Inferred from Comparative Gene Mapping.
abstract: Sex determination in frogs (anurans) is genetic and includes both male and female heterogamety. However, the origins of the sex chromosomes and their differentiation processes are poorly known. To investigate diversity in the origins of anuran sex chromosomes, we compared the chromosomal locations of sex-linked genes in 4 species: the African clawed frog (Xenopus laevis), the Western clawed frog (Silurana/X. tropicalis), the Japanese bell-ring frog (Buergeria buergeri), and the Japanese wrinkled frog (Rana rugosa). Comparative mapping data revealed that the sex chromosomes of X. laevis, X. tropicalis and R. rugosa are different chromosome pairs; however, the sex chromosomes of X. tropicalis and B. buergeri are homologous, although this may represent distinct evolutionary origins. We also examined the status of sex chromosomal differentiation in B. buergeri, which possesses heteromorphic ZW sex chromosomes, using comparative genomic hybridization and chromosome painting with DNA probes from the microdissected W chromosome. At least 3 rearrangement events have occurred in the proto-W chromosome: deletion of the nucleolus organizer region and a paracentric inversion followed by amplification of non-W-specific repetitive sequences.
authors.affiliation: Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Uno
authors.forename: Chizuko
authors.initials: C
authors.lastname: Nishida
authors.forename: Chiyo
authors.initials: C
authors.lastname: Takagi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Igawa
authors.forename: Naoto
authors.initials: N
authors.lastname: Ueno
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sumida
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Matsuda
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura / Q000235:genetics*; D001483:Base Sequence; D002478:Cells, Cultured; D002874:Chromosome Mapping; D020223:Chromosome Painting; D055028:Comparative Genomic Hybridization; D019143:Evolution, Molecular; D005260:Female; D005819:Genetic Markers; D014644:Genetic Variation; D008297:Male; D008969:Molecular Sequence Data; D011003:Ploidies; D011898:Ranidae / Q000235:genetics; D016415:Sequence Alignment; D017385:Sequence Homology; D012730:Sex Chromosomes / Q000235:genetics* / Q000648:ultrastructure; D019849:Sex Determination Processes / Q000235:genetics*; D013045:Species Specificity; D014981:Xenopus / Q000235:genetics
chemical_list: D005819:Genetic Markers