Estimation Of Genetic Parameters And Identification Of Related Molecular Markers Of Egg Number In Teh-Ha Hybrid Fecal Stoecia Of Sheep

Alimentary tract nematode infection in sheep is one of the main factors affecting the health of grazing animals in the world.Alimentary tract parasitic infection can not only reduce the production level of sheep,but also increase the mortality of sheep with disease.The current treatment of parasitic infections focuses on drug deworming,but continued drug intake can lead to drug resistance in sheep and drug residues in animal food.Fecal egg count(FEC)is a quantitative indicator of infection level in sheep.The aim of this study was to estimate the genetic parameters of fecal worm egg number of Terha crossbred lambs and identify the related molecular markers,so as to provide theoretical basis for the nematode-resistant breeding plan of new terha crossbred sheep groups.First analyzes the influence of ha hybrid lamb number of eggs,birth weight,weaned weight,weight of 6 months of age and the influence factors of the average daily gain,secondly by animal model of these properties on the ha hybrid lamb,genetic parameter estimates of variance components,further using genome-wide association analysis to identify the sheep nematode disease resistance related molecular markers,the results are as follows:(1)Through the mixed linear model of ASReml software,the influencing factors of these five traits of lambs were analyzed.It was found that the group and group of lambs had extremely significant effects on all traits(P<0.001).Sex had significant effects on egg number,birth weight,weaning weight and average daily gain(P<0.001),but had significant effects on weight at 6 months of age(P<0.01).Birth type had significant effects on birth weight,weaning weight,6-month-old weight and average daily gain(P<0.001),but had no significant effects on egg number(P>0.05).Age had significant effects on birth weight,weaning weight,6-month-old weight and average daily gain(P<0.001),but had no significant effects on egg number(P>0.05).(2)The genetic parameters of the five traits were estimated by using the animal model in ASReml software,and the heritability of each trait in Terha crossbred lamb ranged from 0.02 to 0.37.Among them,egg number(0.142±0.111),birth weight(0.156±0.110)and 6-month-old weight(0.294±0.186)were medium heritability traits(0.1 ≤ h2 ≤0.3),weaning weight(0.365±0.195)were high heritability traits(h2 >0.3).Average daily gain(0.024±0.077)was a low heritability trait(h2 <0.1).(3)Genome-wide association analysis using PLINK 1.90 software revealed that five SNPs significantly correlated with fecal egg number were located on chromosome 3,6 and 11,respectively,and their adjacent genes were MMRN1,USP15,JUP,VAV2 and TECRL.