Centromere repositioning in the X chromosome of XO/XO mammals, Ryukyu spiny rat.
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.
Kobayashi
Tsuyoshi
T
Laboratory of Animal Cytogenetics, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo, Japan.
Yamada
Fumio
F
Hashimoto
Takuma
T
Abe
Shintaro
S
Matsuda
Yoichi
Y
Kuroiwa
Asato
A
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*
D018076:DNA, Complementary