CYTOGENETICAL STUDIES ON FISHES, III. MULTIPLE SEX CHROMOSOME MECHANISM IN THE FILEFISH, STEPHANOLEPIS CIRRHIFER

抄録

The chromosome number of the female filefish, Stephanolepis cirrhifer, was thirty-four (2n=34), all of which were acrocentrics. In the males of this species, however, the number was thirty-three (2n=33), among which one large metacentric chromosome was always included. Haploid chromosome numbers in the secondary spermatocytes showed n=16 and n=17. In the former cells, one large metacentric chromosome found in the somatic and germ cells seemed to be a Y element. Thus, the sex chromosome mechanism in this species is inferred to be a multiple system, namely X₁X₁X₂X₂ in the female and X₁X₂Y in the male.