The genetic architecture of phenotypic diversity in the Betta fish ( <i>Betta splendens</i> )
Wanchang Zhang, Hongru Wang, Débora Y. C. Brandt, Beijuan Hu, Junqing Sheng, Mengnan Wang, Haijiang Luo, Yahui Li, Shujie Guo, Bin Sheng, Qi Zeng, Kou Peng, Daxian Zhao, Shaoqing Jian, Di Wu, Junhua Wang, Guang Zhao, Jun Ren, Wentian Shi, Joep H.M. van Esch, Sirawut Klingunga, Rasmus Nielsen, Yijiang Hong
Abstract
The Betta fish displays a remarkable variety of phenotypes selected during domestication. However, the genetic basis underlying these traits remains largely unexplored. Here, we report a high-quality genome assembly and resequencing of 727 individuals representing diverse morphotypes of the Betta fish. We show that current breeds have a complex domestication history with extensive introgression with wild species. Using a genome-wide association study, we identify the genetic basis of multiple traits, including coloration patterns, the “Dumbo” phenotype with pectoral fin outgrowth, extraordinary enlargement of body size that we map to a major locus on chromosome 8, the sex determination locus that we map to dmrt1 , and the long-fin phenotype that maps to the locus containing kcnj15 . We also identify a polygenic signal related to aggression, involving multiple neural system-related genes such as esyt2 , apbb2 , and pank2 . Our study provides a resource for developing the Betta fish as a genetic model for morphological and behavioral research in vertebrates.