| fluctuation in abundance and age structure of a breeding population of the japanese brown frog, rana japonica gunther (amphibia, anura). | a breeding population of rana japonica was studied at a marsh on the campus of hiroshima university in higashi-hiroshima during the five years 1995-1999. the mark-recapture study showed that the size of the breeding population varied from year to year, and increased more than twofold in 1999 in comparison with the preceding years. the sex ratio of the breeding population (male/female) was from nearly 1.0 to 1.6. frogs of both sexes were estimated to breed for the first time at the age of one or ... | 2002 | 12125932 |
| 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. | 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 g ... | 1998 | 9866197 |