Study On Genetic Variations Of Xinjiang Brown Cattle’s Lactation-Related Genes And Their Association With Milk Traits

As a unique breed resource in Xinjiang,Xinjiang Brown Cattle has excellent characteristics such as high milk fat protein,low somatic cell number,strong resistance to adversity and good adaptability.So far,the conventional breeding of Xinjiang brown cattle has been improved,but there were few studies on molecular breeding,and a large number of important gene resources related to InDel and SNP contained in the genomic information of Xinjiang brown cattle have not been effectively mined and identified.This study took Xinjiang brown cattle(388)as the research object,and determined FHIT、DYRK2、SPRY1、PRLR、CDH2、GABRG2、KIF1A、EPRS、ANKFN1、SHISA9 according to the previous GWAS results and SNP locus,through Ensemble database to determine the insertion/deletion(InDels)loci of all genes,design the corresponding primers according to the polymorphic locus screened,use PCR amplification,agarose Techniques such as gel electrophoresis and sequencing were used to verify the InDels locus,and the existing InDels locus was individualized,and the typing results were correlated with Xinjiang brown cattle and milk traits.The aim is to study the correlation between the genetic polymorphisms and Xinjiang brown cattle and milk traits,and provide a theoretical basis for the application of Xinjiang brown cattle related genes in cattle breeding,and then provide an important reference for Xinjiang brown cattle breeding and breed improvement.The results of the study are as follows:1.This study detected a SNP locus in the EPRS gene of Xinjiang brown cattle,which is related to the 305 milk production of the second parity,and the milk fat percentage,milk fat yield,milk protein percentage and milk protein yield of the third parity.The somatic cell count of the fifth parity have a significant effects;this loci has a very significant effects on the milk protein yield of the third parity;all the milk traits of the AA genotype at this SNP loci are higher than those of the AG genotype,indicating that the EPRS gene AA genotype has a positive effect on the milk traits of Xinjiang brown cattle.2.Eight InDel loci were detected in the FHIT gene of Xinjiang brown cattle,all of which have significant effects on different milk traits in six parities of Xinjiang brown cattle;One InDel locus was detected in Xinjiang brown cattle DYRK2 gene,this locus has significant effects on the milk production of Xinjiang brown cattle at the first parity 305 days,the milk production at the second parity 305 days,milk protein content and somatic cell number,and the milk protein rate at the sixth parity;Among them,this locus has a very significant impact on the 305-day milk production of the second parity and the milk protein rate of the sixth parity.One InDel locus was detected in the SPRY1 gene of Xinjiang brown cattle.The milk fat percentage and milk fat content of the fourth parity,and the milk protein content of the sixth parity had a significant effect.3.The FHIT gene encodes 148 amino acids,the fat coefficient is 79.13,and the average hydrophilicity is-0.368(<0),indicating that the protein is relatively hydrophilic and is a hydrophilic protein.The subcellular location prediction of FHIT provides a certain reference for studying the function of bovine FHIT gene.The speculation results show that the FHIT protein has no obvious transmembrane structure,so it is speculated that it is not a secreted protein and cannot be transmembrane transfer or localization.It mainly exerts its performance in the cytoplasm and mitochondria.In conclusion,9 genes related to lactation traits in Xinjiang brown cattle were identified in this study,which provides a basis for further research on molecular marker-assisted breeding in Xinjiang brown cattle.However,the specific regulation mode of these genes still needs to be further clarified by subsequent functional verification.