Body color development and genetic analysis of hybrid transparent crucian carp (Carassius auratus)

The aim of this study was to investigate the genetic mechanism of the transparent trait in transparent crucian carp. We observed body color development in transparent crucian carp larvae and analyzed heredity of color in hybrids produced with red crucian carp, ornamental carp, and red purse carp. The results showed that the body color of the newly hatched larvae matured into the adult pattern at approximately 54 days post-hatching. Two inter-species reciprocal crosses between transparent crucian carp and red crucian carp, and self-cross F1 of transparent crucian carp and self-cross F1 of red marking transparent crucian carp were conducted, and results indicated that the transparent-scaled trait is dominant over the normal-scaled trait. Furthermore, the transparent trait is a quantitative trait. All offspring in the four inter-genera reciprocal crosses of transparent crucian carp with ornamental carp and red purse carp were hybrids of common carp and crucian carp, and had a relatively low survival rate of 10-20%. Moreover, the transparent-scaled trait was observed to be dominant over the normal-scaled trait in the hybrid fish. In conclusion, our results suggest that the genetic mechanism underlying the color of goldfish is complex and requires further investigation.