QTL Analysis On Out-season Lambing Traits Of Sheep

Seasonal breeding is one of the bottleneck during the modern efficient sheep reproduction. Thetrait of sheep lambing is controlled by the quantitative character, and the heritability is low. It isdifficult to select in their early stage by using the conventional breeding skills and wasted of time.But the location of QTL analysis on out-season lambing traits of sheep provides a feasibility planfor this problem. In this study, the year-round estrus German meat Merino sheep were selected asmale parents, hybridized with the seasonal estrus China Merino sheep ewe as the female parents.By selfing within the F1generation, obtained the F2with difference in the non-breeding seasontraits, and build lambing trait character reference family, by using self-developed EST-SSR andmicro-satellite have been published to build reference family genetic linkage map. Determine thebreeding season ewes the changes of serum progesterone secretion and the breeding season inewes lambing ability score, by using the method of least squares linear regression analysis,GRIDQTL software running on the behavior of the breeding season sheep related QTLlocalization analysis, lambing trait to sheep breeding season main gene localization, research anduse of lay the foundation. The results obtained were as follows:1. This study selected twenty male German meat merino sheep and seasonal estrus2200ewes of China Merino sheep as parents lead to hybridization experiment, obtain F1seed20rams,and1850ewes,490F2ewes, BC160, total4740sheep, and constructed the large sample referencesheep family of breeding season.2. his study by measuring heat and non-estrous Chinese merino sheep breeding of varyingconcentrations of serum E2, LH and P4. Results showed that in the non-breeding season, E2concentration keep at lower levels, the average concentration was in the9.99-12.83pg.ml-1range,lower than the breeding season estrus within24hours of18.47-19.54pg.ml-1; LH concentrationfluctuates up and down in the1.0ng.ml-1; without breeding season peaks of ovulationappearance.Progesterone levels remain in a low range,and the average concentration between0.25and0.29ng.ml-1.3. Female serum content of progesterone may determine the ability of lanbing in non-breedingseason. Results showed that the F2progesterone cycle was detected in female individuals to60,irregular change individual for22,1and2times to detect periodic changes in the progesteronesecretion of ewes number35and30, respectively, to detect three progesterone cycles for11.Progesterone cyclical change tip in the breeding season ewes has the ability of ovulation, F2ewesbetween individuals in the breeding season reproduction perform differences.4. Found the EST-SSR in the brain and ovary of sheep, and the correlation with the lambing andbirth weight were analyzed. The results showed that the loci had rich polymorphism and23alleleswas detected among6loci in the group.The range of heterozygosity(H) was0.5851to0.7766, and the polymorphism information content of all loci (PIC) were higher than0.5.EST622,EST463,EST561loci were eligible for Hardy-Weinberg equilibrium. The resultsindicated that six loci had significant effect on reproduction traits. The loci of EST418related withaverage birth weight and total birth weight, EST463and EST122loci with total birth weight andlambs born, EST622and EST561loci with total birth weight, EST182loci with total lambs born. Itis suggested that these six loci probable have high linkage with genetic locus of reproductiontraits.5. This study selected the genealogical information clear F2158ewes, including F1and parentsa total of460individuals, chosen107microsatellite loci and2EST-SSR loci, using Crimap2.4group of genetic linkage map construction. The results showed:Constructed including1,2,4,5,6,7,8,12,13,16,19,20,25chromosome chain group of a total of13genetic linkage map, map totallength, total length of1738.4cM; each group chain length between69.9and250.4cM, differentlinkage groups on the tag number in5-12. With sheep in NCBI SM4.7contrast between tag order.6. According to the result of the breeding season Ram testing and serum progesterone,combined with the conditions of lambing on breeding season in F2ewes ability lambing rate,running GridQTL software, positioning affects sheep breeding season lambing ability and thenumber of progesterone cycles QTL. Results show that effect the ability of the sheep the breedingseason lambing QTL mapping on chromosome1,2,19, influence of breeding season progesteronecycle count sheep chromosome QTL mapping in25, F test5%of chromosome level significantly.