The Journal of Heredity 1995:86(2):114-120
© 1995 The American Genetic Association 86:114-120
research-article |
Variation of Repetitive DNA and its Phylogenetic Relation in Hynobiidae (Caudata)
Laboratory of Molecular Biology, Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981, Japan
Laboratory of Molecular Biology, Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University and the Department of Applied Biological Sciences, Science University of Tokyo Japan
Abstract
Middle repetitive (MR) DNA comprising about 35% of the genomic DNA of Hynobius retardatus was isolated and used as mixed probes. A 1.3-kb BamHI fragment, the major repeating unit of the extensively amplified sequences in H. retardatus, was cloned, sequenced, and used as a probe. Dot blot hybridization under the conditions of probe excess revealed that the MR DNA sequences were shared among the three salamander genera belonging to the family Hynobiidae. However, a large difference in the amount of common sequences was found between Hynobius and Salamandrella, and large differences in both amounts and sequence similarity were found between Hynobius and Onychodactylus. Even among species belonging to the genus Hynobius, relative contents of sequences common to the H. retardatus MR DNA were 20% to 50%. Partially related sequences to the 1.3-kb sequence seemed to the present in all the species of Hynobius and Salamandrella, but the extensive amplification was found only in H. retardatus. Based on the relative contents of the common MR DNA and previously reported chromosomal banding characteristics, species in the genus Hynobius are classified into at least three groups. An evolutionary aspect of the emergence of the amplified sequence in H. retardatus is discussed.