Molecular genetic analysis of phylogenetic relationships in the genus Hynobius by means of Southern blot hybridization

Abstract

Variations in repetitive DNA were examined in nine salamander species of the genera Hynobius and Onychodactylus. The data from Southern blot hybridization were processed by Manhattan distance analysis, and unrooted trees were drawn. The resulting trees suggest that the genus Hynobius can be divided into three groups: group 1 contains only H. retardatus with 40 chromosomes; group 2 contains H. kimurae, which has 58 chromosomes and is a mountain-brook type of Hynobius (this group probably contains all mountain-brook types of Hynobius with 58 chromosomes); and group 3 contains the other six pond-type species examined here, each with 56 chromosomes. Group 3 probably contains all species of Hynobius with 56 chromosomes. Furthermore, group 3 can be further separated into two groups: the first group includes H. leechii, H. tsuensis, H. nebulosus, H. nigrescens, and H. tokyoensis from Chita; and the second group includes H. tokyoensis (except the population from Chita) and H. lichenatus. According to this analysis and other information, it seems that the population from Aichi Prefecture, which belongs to H. tokyoensis, should be identified as H. nebulosus. Furthermore, it appears that the genus Onychodactylus is phylogenetically distant from Hynobius and Salamandrella.Key words: Hynobius, repetitive DNA, Southern blot hybridization, phylogenetics, neighbor-joining method.