Study On Variation And Expression Of MC1R Gene In Zhedong White Geese And Langde Geese

Coat color is available economic traits and genetic markers, it is in determining the species purity, and relationship crosses play an important role. Sequence variation in the melanocortin-1 receptor gene (MCIR) is associated with melanistic phenotypes in many vertebrate taxa, including several avian species. Consequently, the MClR gene is a candidated gene for melanin trait of many animals. In our study, the gray plumage Landes, the variegated plumage Landes (gray and white), and the White plumage Zhedong White Goose's MClR gene genetic variation were studied with the PCR product direct sequencing method. The MClR gene expression was studied by fluorescence quantitative PCR reaction.We sequenced 714 bp of the MClR coding region in 176 individuals spanning the range of plumage variation. Through bioinformatics analysis, we found the A T content of the obtained sequence was 40.20%, the GC content was 59.52%, the AT content is much lower than GC. The homology of the obtained sequence from samples and partial MClR gene of geese was as high as 99%.By screening single nucleotide polymorphism sites in all individuals, we found five SNPs sites,210C>T,321C>T,411C>T,525C>T,756G>A, all of them were singleton variable sites. Three mutations,210C>T,321C>T,756G>A were only in the Zhedong White Goose, two variation sites,411C>T,525C>T were only in Landes. After the sequences alignment, we found that all the five SNPs sites in Zhedong White Goose and Landes were novel SNPs, but all were synonymous mutations. The results of alignment showed seven haplotypes, haplotype Z2 (C-C-C-C-G) and Z4 (C-C-T-C-G) were the dominant haplotype, Z2Z2 and Z4Z4 haplotype combination were the dominant haplotype combinations. The chi-square test results showed that the five mutations in different haplotypes and geese have reached highly significant level, indicating that MClR gene have a significant impact in geese plumage traits, suggesting that MClR gene is the main candidate genes for geese plumage traits.In order to detect the expression of MClR gene in mRNA level, quatitative PCR was conducted, which showed that MClR gene has the highest expression in 1 day-old skin Zhedong White Goose, while the Landes' was in 28 day. For the same time, the expression difference in all the time points reached significant or highly significant level except the 1 day and 21 days between Zhedong White Geese and Landes Geese. For the same species at different time points, the expression difference between 1 day and other days reached significant or highly significant in Zhedong White Goose, Landes 28 days between other days (except 14 days) expression difference reach the significant or highly significant. The expression pattern may be related to species and molt to a certain extent.