Frequencies of the acrocentric homomorphic (A/A), the acrocentric and subtelocentric heteromorphic (A/S) and the subtelocentric homomorphic (S/S) types in the pair nos. 1 and 9 of the black rats are examined in 46 specimens collected in the Osaka-city of Japan. A considerably high frequency of the A/S and the S/S types observed in these specimens is rather similar to those distributed in the Kanto district of Japan. These features are explained by the historical migration events of the black rats.
Electrophoretic Hbb patterns of 152 specimens in the black rats (R. rattus) collected from the harbor area of Shimizu port and the vessels from Korea, Japan, Indonesia and Taiwan, anchoring in the port, and obtained from the laboratory colonies are analyzed by the Titan III cellulose acetate electrophoresis. The Hbb pattern classified into three types (Hbba, Hbbab and Hbbb), and it is demonstrated to be polymorphic in two alleles codominant.