Linkage Map Construction Of The 3～(rd) Chromosome And QTL Mapping Of Weight Traits In Liangshan Semi-fine Wool Sheep

A referencing flock comprising eight paternal half-sib families totaling 275 individuals from Liangshan semi-fine wool sheep was utilized to build a framework linkage map of the 3rd chromosome. Phenotypic data of five traits, namely birth weight(BW), weaning weight(WW), weaning daily gain(WDG) , 1.5-yeal weight(1.5-YW) and 2.5-year weight(2.5-YW), was analyzed based on daughter design to locate the putative QTL affecting the relevant traits.The average number of alleles, average PIC and average heterozygosity of microsatellites were 7 (from 3 to 9 ), 0.605 (from 0.386 to 0.820) and 0.608 (from 0.408 to0.802) respectively. And all markers were high or middle polymorphic, which could substantially guarantee the reliability of the result of the research.The sex average linkage map of the 3rd chromosome of Liangshan semi-fine wool sheep was constructed by Crimap (2.4). The complete length of the map was 339.8cM, which had an average marker interval of 42.5cM as well as the maximum and minimum interval of 66.2cM (BMS1248-BM2830) and 9.1cM (ILSTS22-BM2830). Besides that, the sequence of loci was coincident with the USDA-MARC,SM4.2 (ARKdb) and Version 4.3 (Australian) ovine map,however most marker intervals were larger than the latter three.Phenotypes of five traits were handled statistically by SAS6.12 in the 156 progenies. The "CORR" consequence revealed the significant correlation between BW and WDG, BW and 1.5-YW, BW and 2.5-YW,1.5-YW and 2.5-YW. Meanwhile, the "GLM" result demonstrated sire factor only has no influence on five weight traits.QTL mapping was accomplished through interval mapping. A couple of software (QTL Express and Win QTLcart), which employ different methods (regression and LR test) separately, were applied to analyze simultaneously. a putative QTL affecting WW was detected around BMS1048 marker both by QTL Express and Win QTLcart,the position were located on 99cM (192 family)and 110. 1cM(191 family) respectively and the difference was 11.1cM. Another putative QTL affecting WDG was detected around BMC 1009 marker both by QTL Express and Win QTLcart,the position were located on 219cM(192 family) and 227.41cM (190 family) respectively and the difference was 8.4lcM. In addition, a QTL that has great effecton 2.5-YW was observed by QTL Express, situating 273cM around BM2830 in 188 family.