The Study On The Variations Of Agouti Gene 5’UTR And ASIP Located Research In Goat

For goat, the variations of UTR in Agouti gene may have relationship with the expression of Agouti gene. This variation may affect the change of coat color. Meanwhile, the variations of promoter affect the activity of promoter. This change of promoter activity can also affect the expression of Agouti gene. The distribution of Agouti gene in goat skin can cause the change of melanin distribution, and cause the coat color phenotypic variation deeply. So reseaching these key questions was an important way to resolve the genetic mechanism of goat coat color.In this study, 30 Jining goats, 30 Liaoning goats, 30 Leizhou goats and 32 Nanjiang goats were chosed to do chromosome walking test. 5’UTR of Agouti gene was sequenced based on the sequences (EF587236.2 and EU185099) from GenBank. The 7357bp fragment which was amplified had been handed out to GenBank, the Accession Number was JN651404. JN651404 joined with EF587236.2 to the length of 12847bp with DNAMAN software. The structure of Agouti gene was predicted by Spidey software. 90bp exon1 and 7267bp 5’UTR were proved in JN651404 and 7679 site was the start of translation of Agouti gene. Then a candidate goat Agouti gene promoter region: 6450-7100bp was predicted by Neural Network Promoter Prediction and TFSEARCH softwareThree point mutations were found in 6450-7100bp, which were g.C6474 T,g.C6579T and g.T6703A. Through population genetic analysis, CC genotype of g.C6474T, CC genotype of g.C6579T and TT genotype of g.T6703A may had relationship with black goat coat color. These three mutations were in linkage disequilibrium and CCT was the ancestral haplotype for JNG, LN, LZ and NJF, it may be also have a relationship with black goat coat color.In this study, 2 white Taihang goats and 1 black Taihang goat were chosed to do RACE test. 88bp fragment was sequenced which was in mRNA of Agouti. Because this fragment was mismatch the 5’UTR of Sheep and pig, there were many exon1 types in different animals, and 5’UTR of goat had not studied. So whether this 88bp fragment was belong to part of goat Agouti gene or not was not sure.In semi-quantitative study, 5 white, 5 black and 5 brown Taihang goats were chosed respectively. The result showed that the order of Agouti gene mRNA amount was white (0.8131±0.0577) > brown (0.5571±0.0736) > black (0.3991±0.0289) in different coat color goats. But in IHC study (3 white, 3 black and 3 brown Taihang goats were chosed respectively), ASIP only expressed in the follicular external root sheath of black and brown coat color goat. No signals were found in the follicular external root sheath, epidermis and dermis of white coat color goat. Meanwhile epidermis and dermis of white, black and brown coat color goat also had no signals exsited.