Abstract
Karyotype variation in the hynobiid salamander, Hynobius tokyoensis, from the northern Kanto area was studied using the conventional Giemsa staining. A total of 229 embryonic individuals from 34 egg capsules collected in seven populations were analyzed. Karyotype variations with respect to chromosome number 10, which may be either submetacentric (SM) or telocentric (T), were found in three populations. Average frequencies of SM/SM, SM/T and T/T examined in these populations were 28.8%, 41.8% and 29.4%, respectively. The remaining four populations did not show such variations; all of 76 individuals examined had homomorphic pairs of submetacentric (SM/SM). We suggest that the telocentric no. 10 chromosome has been derived from the submetacentric homologue in a limited area of the northern Kanto area. We also analyzed the frequency of chromosome variation in each egg capsule from the polymorphic populations, and present a possible combination of the parent karyotypes.
