Association Between Novel Polymorphism In SCD And CDC10 Gene And Fatty Acid Composition In Ujimqin Sheep

Ujimqin sheep is one of the Mongolia sheep breeds,is favored by consumers because of its fresh,tender meat and high nutritional value.Recent studies have showed that SCD and CDC10 genes are related to fatty acid(FA)composition and adipose deposition.The SCD gene is a key enzyme in the process of saturated fatty acid(SFA)desaturation to unsaturated fatty acid(UFA),which affects the composition of FA,and then affects the nutritional value and flavor of meat;The CDC10 gene can affect intramuscular fat deposition by regulating cell cycle,thereby affecting the grade of marbling.We speculated that SCD and CDC10 genes may be important candidate functional genes affecting the meat quality of Ujimqin sheep.In order to investigate the association between SCD and CDC10 genes polymorphism and FA composition in the longissimus dorsi muscle of Ujimqin sheep.In this study,the FA composition in the longissimus dorsi muscle of 244 Ujimqin sheep were detected for analyzing the correlation between FAs.The polymorphism of SCD and CDC10 genes in 12 Ujimqin sheep was identified by direct sequencing,and then we genotyped the polymorphism of SCD and CDC10 genes in 244 Ujimqin sheep using MassARRAY technology.In addition,we analyzed the genetic diversity of polymorphism and the association of polymorphism with FA component in Ujimqin sheep.The results are as follows:(1)A total of 30 FA components(including 15 kinds of SFA and 15 kinds of UFA)were detected in the longissimus dorsi of Ujimqin sheep.Correlation analysis between each FA showed that C13:0 was positively correlated with C18:2n6t,C21:0 was positively correlated with C20:3n6,MUFA was positively correlated with MUFA/SFA,EFA and PUFA was positively correlated with PUFA/SFA(P = 1.00).(2)The identification of polymorphism in SCD and CDC10 genes showed that a total of four polymorphism were found in SCD gene,which are g.21032436G>A(intron 3),c.498G>A(exon 4),g.21032827A>C(intron 4)and c.828C>T(exon 5).A total of five polymorphism were found in CDC10 gene,which are g.62910998C>T(promoter),g.62868889T>C(intron 3),g.62843724T>C(intron 5),g.62835677A>C(intron 6)and g.62812866G>A(intron 12).(3)The results of genetic diversity showed that except for the c.498G>A single nucleotide polymorphism(SNP),the other mutations were consistent with Hardy-Weinberg equilibrium(P > 0.05).(4)The results of association analysis showed that the individuals with AC genotype in g.21032827A>C SNP of SCD gene have significantly higher C22:6n3 than those of AA genotype(P < 0.05);The individuals with CT genotype were significantly higher C11:0 and MCFA than those of CC genotype,and C14:0 of individuals with CC genotype were significantly higher than those of CT genotype in c.828C>T SNP(P <0.05);The C17:1 of individuals with AG genotype was significantly higher than those of AA genotype in g.21032436G>A SNP of SCD gene(P < 0.05).The C18:1n9t of individuals with TT genotype were significantly lower than those of TC genotype in g.62843724T>C SNP of CDC10 gene(P < 0.01).(5)Bioinformatics analysis showed that synonymous mutations at c.498G>A and c.828C>T sites of SCD gene predicted to change m RNA secondary structure,thereby probably affecting the function of SCD gene.In summary,the g.21032827A>C and g.21032436G>A SNP of SCD gene and the g.62843724T>C SNP of CDC10 gene were all significantly related to the UFA in the longissimus dorsi muscle of Ujimqin sheep,which could be an effective molecular genetic marker to improve meat quality of Ujimqin sheep and provide a scientific basis for the genetic improvement of Ujimqin sheep.