TY - JOUR
T1 - The origin and differentiation of the heteromorphic sex chromosomes Z, W, X, and Y in the frog Rana rugosa, inferred from the sequences of a sex- linked gene, ADP/ATP translocase
AU - Miura, Ikuo
AU - Ohtani, Hiromi
AU - Nakamura, Masahisa
AU - Ichikawa, Youko
AU - Saitoh, Kazuo
PY - 1998/12
Y1 - 1998/12
N2 - Sex chromosomes of the Japanese frog Rana rugosa are heteromorphic in the male (XX/XY) or in the female (ZZ/ZW) in two geographic forms, whereas they are still homomorphic in both sexes in two other forms (Hiroshima and Isehara types). To make clear the origin and differentiation mechanisms of the heteromorphic sex chromosomes, we isolated a sex-linked gene, ADP/ATP translocase, and constructed a phylogenetic tree of the genes derived from the sex chromosomes. The tree shows that the Hiroshima gene diverges first, and the rest form two clusters: one includes the Y and Z genes and the other includes the X, W, and Isehara genes. The Hiroshima gene shares more sequence similarity with the Y and Z genes than with the X, W, and Isehara genes. This suggests that the Y and Z sex chromosomes originate from the Hiroshima type, whereas the X and W chromosomes originate from the Isehara-type sex chromosome. Thus, we infer that hybridization between two ancestral forms, with the Hiroshima-type sex chromosome in one and the Isehara-type sex chromosome in the other, was the primary event causing differentiation of the heteromorphic sex chromosomes.
AB - Sex chromosomes of the Japanese frog Rana rugosa are heteromorphic in the male (XX/XY) or in the female (ZZ/ZW) in two geographic forms, whereas they are still homomorphic in both sexes in two other forms (Hiroshima and Isehara types). To make clear the origin and differentiation mechanisms of the heteromorphic sex chromosomes, we isolated a sex-linked gene, ADP/ATP translocase, and constructed a phylogenetic tree of the genes derived from the sex chromosomes. The tree shows that the Hiroshima gene diverges first, and the rest form two clusters: one includes the Y and Z genes and the other includes the X, W, and Isehara genes. The Hiroshima gene shares more sequence similarity with the Y and Z genes than with the X, W, and Isehara genes. This suggests that the Y and Z sex chromosomes originate from the Hiroshima type, whereas the X and W chromosomes originate from the Isehara-type sex chromosome. Thus, we infer that hybridization between two ancestral forms, with the Hiroshima-type sex chromosome in one and the Isehara-type sex chromosome in the other, was the primary event causing differentiation of the heteromorphic sex chromosomes.
KW - ADP/ATP translocase
KW - Frog
KW - Rana rugosa
KW - Sex chromosome
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M3 - Article
C2 - 9866197
AN - SCOPUS:0031773526
VL - 15
SP - 1612
EP - 1619
JO - Molecular Biology and Evolution
JF - Molecular Biology and Evolution
SN - 0737-4038
IS - 12
ER -