Genetic Basis On Skin Color Difference In Two Distinct Strains “Whole Red” And “Whole White” Of Oujiang Color Carp

Oujiang color carp(Cyprinus carpio var. color) distributes around Oujiang river basin in Zhejiang province in southeast part of China. It has been domesticated for over 1,200 years. Several color patterns are observed, such as whole red, red with scattered black spots, whole white, white with scattered black spots, etc. Since 2000, studies have been carried on the genetic diversity and exploitation and utility of Oujiang color carp. In color inheritance of common carp, red and white color phenotypes are recessive to normal color(light black color) phenotype. The red and white color phenotypes which indenpendently inherit were studied through hybridization using "whole red" and "whole white" patterns of Oujiang color carp. All individuals of F1 progeny were red, while there were both whole red and whole white in F2 progeny. We assume that the trait of red/white color was controled by one gene or a cluster of linked genes. The Oujiang color carp "whole red" and "whole white" populations were ideal materials for study of mechanism of body color.First of all, we take advantage of the 250 K high-throughput SNP array for whole genome-wide association analysis with 108 “whole red” and 105 “whole white” Oujiang color carps. Finally, we find out 36,920 genetic differences loci between the two group carp data from 199,233 SNPs in chip. Then we located two functional gene : melanocyte proliferating gene 1(MYG1)and Fibroblast growth factors 7(FGF7)near the hight significant site. We speculate that MYG1 and FGF7 may induced the proliferation of epidermal melanocytes as the potential gene control the body color of carp.Secondly, we apply pooled sequencing basing on BSA(bulk segregant analysis) on samples from the "whole red" and "whole white" populations described above. After mapping to common carp reference genome sequence, we find out 69,114,695 SNPs, combining with common carp genome annotation database, we obtain another copy of FGF7 in carp genome which Confirm the possibility of FGF7 gene is the body color related genes. Additionally, we perform Phylogenetic analysis and expression analysis with FGF gene family in common carp from this we demonstrate the FGF7 expressed in skin.