Study On Phenotypic Diversity And MITF Gene Polymorphisms Of Spotted Horse

Spotted fur is the base of a certain color coat,the spotted horse's whole body scattered with color of spots and the spot's large and distributions is irregular.There were only about 300 of spotted horse and near to extinction in Xinjiang.MITF is a kind of gene which is related to fur color,which can play a decisive role in caot color by affecting the development,function regulation and differentiation of pigment cells.However,no report has been reported on the main effect genes and mechanism of xinjiang spotted horse caot color.so in this study,Firstly,through the visual observation analyzed the coat color type and appearance characteristics of 63 spotted horses and measured the normal body size in the survey in Xinjiag.in order to distinguish the differences in the physical features and body size indexes between xinjiang spotted horses,kazakh horses and Mongolian horses,the body ruler was compared and analyzed;Secondly,In order to do a good job in the selection of spotted horses,the physical appearance identification standard method was used to observe the physical appearance of each phenotype of 23 types of xinjiang spotted horses that we encountered during the investigation;Finally,To identify genes associated with the colour MITF gene mutations,horse MITF gene nucleotide distance and spot color between phenotypic correlation analysis and reveal the genetic mechanism of the influence spotted horse coat color,which spotted horse breeding research and production management to provide basic data.By using the Codon analysis,SNP site detection,neutral analysis,Genetic polymorphic parameter analysis,MITF gene nucleotide distance analysis,Clustering analysis to performed on all exons(11)of the coat color candidate gene MITF.The results are as follows:1?The study found that the spotted horse was divided into 23 species by the differance of the base coat color and the spots color of the spotted horse,It is shown that the color and pattern of the spotted horse is more complicated and the appearance is different from other local breeds;The average height of the spotted horse was 138.82 cm,the body length was 141.10 cm,the chest circumference was 160.85 cm and the tube circumference was 160.85 cm.Calculated body size index can be known that the rate of body length is101.64%,the rate of chest circumference is 115.86%,the rate of tube circumference is 13.74%,It can be seen that the spotted horse is a riding horse;The spotted horse and the kazakh horse's body size index are relatively close,it may be the result of mixed hybridization by long-term grazing.2?Spotted horse's body is more complex,adverse environmental endurance is strong,constitution is moist solid model;The maximum variation coefficient(17.74%)was found in spotted horse,which had great potential for breeding in weight.The correlation coefficient between the body ruler of the spotted horse is positive,that is,positive correlation.The correlation between the weight and chest circumference of spotted male mare was the largest,and the body length was second.3?The G+C content of the kazakh horse's MITF gene(0.409)was larger than the G+C content of the spotted horse's MITF gene(0.4083),In addition,the codon bias of the spotted horse is stronger than the kazakh horse,so there is a mutation in the base of DNA spotted horse MITF gene;The Tajima's D value(-2.19639)and Fu and Li's D value(-1.66536)of the MITF coding region obtained by two test methods of spotted horse neutral analysis were both negative.The MITF gene has a selective effect in the domestication of the spotted horse and kazakh horse;There were 96 synonym mutation sites in the spotted horse MITF gene,Among them,there were 25 abnormal mutation sites,accounting for 20.66% of the total number of mutations;The RSCU value of codon AGA-R?CCA-P?AGG-R?AGC-S?GCA-A?UUA-L areall higher than one,so the use frequency of these codon is high;There is no much difference between the genotype frequency and gene frequency of the spotted horse and kazakh horse.The correlation coefficient between the base coat and speckled wool and white wool is the largest.There was a very significant(1.000)or significant(0.933)mean,indicating that the dominant mutation of the MITF gene was associated with the white hairy phenotype of the spotted horse;There were 23 mutant sites in th spotted horse MITF gene,15 sites of them happen base conversion,the base deletion occurred at 8 sites;The genetic distance of the spotted horse population and the kazakh horse population is not far away,and it is closely related to each other.it is needed to Further study for the relative expression and protein level expression of the spotted horse MITF gene in each hair color phenotype.