| A primary genomic screen for quantitative trait loci (QTL) affecting wool traits was performed by analyzing 9 microsatellites within 245 progeny from 8 half-sib families of Liangshan semi-wool sheep. A total of 387 individuals were genotyped for all markers. The average number of alleles was 8.44, the mean observe heterozygosity was 0.643, and the average PIC was 0.604. 7 of 9 microsatellites are highly polymorphic (PIC0.5) . Therefore these markers could be used to the construction of linkage map and detection of quantitative trait loci. In the meanwhile, the following traits were analyzed: weaning staple length (BMC), weaning wool fine (BXD), 18-months staple length (CMC), 18-months wool fine (CXD), 18-months abdomen staple length (CFM), 18-months fleece weight (CJML), 30-months staple length (DMC), 30-months fiber diameter (DXD), 30-months abdomen staple length (DFM), 30-months fleece weight (DJML).A linkage map of Liangshan semi-wool sheep (Chromosomes 1) were built by Crimap (V2.0) after paternity test on every offspring. The length of the sex-average map was 311.0 cM. The average interval distance was 38.9 cM, the minimum interval distance was 17.8 cM (between BMS6465 and BMS1636), and the maximum interval distance was 58.8 cM (between MCM58 and BMS2321).The phenotypes of 245 progenies were analyzed by SAS V6.12 software. There were evidences demonstrating great correlation between BMC and CMC, CMC and DMC, CMC and CJML, DMC and DJML. The ANOVA analysis result indicate: there were evidences demonstrating the main factor of family had significant effect on BMC, CMC, DMC , DFM, and DJML; the main factor of age had significant effect on BMC, CJML, DJML,DMC and DXD.QTL analysis was performed by two software (QTL express and WINQTLcart) utilizing different methods, thus linear regression model and likelihood ratio test. The empirical threshold values were computed by permutation for 1000 times, and confident intervals were measured by bootstrapping. There were two putative QTLs which surpass the chromosomal-wide significant threshold both through QTL express and WINQTLcart. A locus (p<0.05) influencing CMC was at 215 cM and 231.6 cM in the result of two software respectively, the positions were slightly varied but still in the same marker interval. On the other hand, QTL which has effect on CXD displayed totally dissimilar characteristic, the locus was at 13 cM in QTL express's consequence while at 203.1 cM in the other. There needs a further study to explain this phenomena. Several QTLs which were significant merely in one outcome of the two software were tested: BMC at 260 cM, CJML at 249 cM 247 cM and 185 cM, DJML at 59 cM, CFM at O.OcM, DMC and DXD at 66.1 cM. |
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