Polymorphisms Of Melanin-related Genes And Their Association With Plumage Color In Duck

Plumage color is an economic trait. It is also an important genetic maker. Previous studies indicated that melanin-related genes play important roles in controlling plumage color. In order to explore the plumage color related genes of ducks, the second generation of white Kaiya×Liancheng and other six species(including Putian duck, Enshi duck,Liancheng duck, White Kaiya, Jingjiang duck and Peking duck) were used as experimental animals. Four genes melanin-related genes, including KIT, ASIP, ATRN and RAB27 A, were chosen as candidate genes. 5’RACE, q PCR and PCR-RFLP methods were performed in this research. The main results are displayed as follows:1. There were three kinds of spliced variants in KIT gene. Of these three, KIT m RNA isoform1 could not be found as a reported KIT m RNA isoform in duck, but it was highly similar to a KIT m RNA isoform of other avian. KIT m RNA isoform 2 spliced by a part sequence of intron 2 and exon 3. KIT m RNA isoform 3 was a special splice by exons with the arrangement of intron 4-5-6-7-2-3-4.2. Our results demonstrated that KIT gene in duck was a muti-copy gene. Copy numbers showed no significant difference among different species of ducks.3. KIT polymorphisms and its association analysis of duck plumage color showed as follows: an 8bp deletion was found in intron1 of KIT, but it is not associated with plumage colors. Furthermore, eighteen SNPs were detected in intron 1, and only 11 SNPs led to restriction sites change. Association analysis showed that only g.912C>G and g.6578G>A sites associated with plumage color(P<0.05). They might cause the difference of plumage color in duck.4. Five SNPs were identified in ASIP gene. None of them led to restriction sites change. Meanwhile, an 11 bp deletion was found in exon 2, but it is not association with plumage colors. Otherwise, our results demonstrated ASIP gene in duck was a muti-copy gene in duck. Copy numbers showed no significant variation among different species of ducks.5. The segregation model of plumage color trait in F2(Liancheng×White Kaiya duck, n=1030) indicated that the proportion of the ducks(n=4) with common phenotype of Liancheng duck was(1/4)4. It was speculated that this trait was controlled by four loci.In this research, A 29 bp deletion was found in ATRN gene. Genotyping revealed that Liancheng ducks and individuals in the second generation with the same characteristic of Liancheng were all homozygous deleted. Meanwhile, two SNPs was found in ATRN and RAB27 A gene respectively, and their genotypical distribution is the same with the result of 29 bp deletion. Therefore, ATRN gene and RAB27 A gene might be two candidate genes that controlled the plumage color trait of Liancheng.In conclusion, KIT gene might be associated with plumage color of duck, while ASIP gene might not. ATRN and RAB27 A genes might be associated with the plumage color of Liancheng.