title: Centromere repositioning in the X chromosome of XO/XO mammals, Ryukyu spiny rat.
abstract: Two species of Ryukyu spiny rat, Tokudaia osimensis and Tokudaia tokunoshimensis, have an XO/XO sex chromosome constitution with no cytogenetically visible Y chromosome in both sexes. The single X chromosomes of T. osimensis and T. tokunoshimensis are submetacentric and subtelocentric, respectively. It was therefore suggested that a pericentric inversion event occurred in the X chromosome of either species. To identify X chromosome rearrangements that have occurred between the two species, we mapped 22 mouse cDNA clones of the X-linked genes on the chromosomes of the two species by direct R-banding FISH. The gene orders of the X chromosomes were conserved in the two species, whereas the position of the centromere on the X chromosome was different. This result indicates that the rearrangement which occurred in either of the X chromosomes after the two species diverged from a common ancestor involved not pericentric inversion but centromere repositioning.
authors.affiliation: Laboratory of Animal Cytogenetics, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Fumio
authors.initials: F
authors.lastname: Yamada
authors.forename: Takuma
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Shintaro
authors.initials: S
authors.lastname: Abe
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Asato
authors.initials: A
authors.lastname: Kuroiwa
mesh_terms: D000818:Animals; D002503:Centromere / Q000378:metabolism*; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian / Q000378:metabolism*; D002999:Clone Cells; D020732:Cytogenetic Analysis; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D050172:Genes, X-Linked; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008322:Mammals / Q000235:genetics*; D051379:Mice; D051381:Rats; D014960:X Chromosome / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary