The ploidy and reproductive mechanism of crucian carp, Carassius auratus gibelio

With the method of Feulgen staining, through cytophotometric measurements, the DNA contents of sex-reversed male (genotypic female) crucian carp (2n = 150 ±) had average values of 2.75 and 1.36 A.U., respectively, in erythrocytes and spermatozoa. The ratio of the erythrocyte and spermatozoon DNA contents of the 'male' crucian carp is 2.01:1 (2C: 1C) and is the same as in the normal male, 2.02:1. The crucian carp has a DNA value of 4.1 pg, which is 68% of that in humans. The results of the study suggest that both sex-reversal males and normal males have the ability to complete the meiotic division during their gametogenesis, and that the population has diploidized over a long term of evolution.