The chromosome behaviors during meiotic division were investigated cytologically in the Bombyx mori strain bearing chromosomal aberration T(23;25)Nd, in which a reciprocal translocation fusing the chromosomes 23 and 25 occurred. The chromosome number (2n=55) in the hetelozygotes for T(23;25)Nd is one less than the normal number (2n=56) of B. mori. The primary spermatocytes in the hetelozygotes were found to have 27 chromosomes including an exceptionally large one, which may be constructed by 3 kinds of chromosomes, T(23;25)Nd, 23 and 25. In each of the secondary spermatocytes the chromosome number was 27. If the meiotic division is prereductional, the number of chromosome in the secondary spermatocytes should be 27 and 28 in a ratio of one to one. When the division is postreductional, the expected number is solely 27. The latter was found to be the case in all secondary spermatocytes, indicating that the male meiosis in this chromosomal mutant is postreductional.
All Science Journal Classification (ASJC) codes
- Polymers and Plastics