The key role of tyrosinase in color variation of the autotetraploid Carassius auratus

• Published in: Aquaculture 2025-03, Vol.598, Article 741952
• Main Authors: Xu, Xi-Dan, Peng, Wan-Jing, Zhou, Yue, Wang, Chong-Qing, Zhang, Kun, Huang, Xu, Xu, Xiao-Wei, Bai, Jin-Hai, Xiong, Ling, Liu, Zheng-Kun, Deng, Xin-Yi, Tang, Yan, Ma, Ming, Qin, Qin-Bo, Liu, Shao-Jun
• Format: Article
• Language: English
• Subjects: Autopolyploidization; Cooperative regulation; Evolutionary process; Tyr
• ISSN: 0044-8486
• DOI: 10.1016/j.aquaculture.2024.741952

The autotetraploid Carassius auratus (4nRR, 4n = 200, RRRR, brownish-yellow coloration), derived from the whole-genome duplication of Carassius auratus red var. (RCC, 2n = 100, RR, red), is a model for understanding the genetics and evolution of polyploid animals. In this study, changes in melanophore and melanin contents indicated differences in melanin metabolism among these two fish species. Tyrosinase (tyr), a key enzyme in melanin biosynthesis, exhibited significant up-regulation in 4nRR, but its role in pigmentation and coloration variation in 4nRR is unknown. Here, color-variant RCC, 4nRR, and their gynogenetic offspring were established and investigated, revealing that 4nRR tyr differentiated from RCC tyr to achieve the effective regulation of 4nRR pigmentation. In RCC, two tyr homeologs have sub-functionalized to synergistically regulate melanogenesis. Furthermore, color variation was tracked at different developmental stages in mutants. Subsequently, four divergent tyr homeologs in 4nRR were localized to four homeologous chromosomes and exhibited predominantly biased expression. Remarkably, yellowish coloration was determined by deficiency of four tyr homeologs rather than single or multiple mutated (