| A referencing flock comprising eight paternal half-sib families totaling 353 individuals from Liangshan semi-fine wool sheep was utilized to build a framework linkage map of the 2nd chromosome. Nine microsatellites were selected and genotyped; then allele frequency, polymorphism information content (PIC) and heterozygosity of these markers were computed within the experimental group. Phenotypic data of five traits, namely birth weight(BW), weaning weight(WW), weaning daily gain(WDG), 18-month weight(18W) and 30-month weight(30W), 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 7.4 (from 4 to 10), 0.590 (from 0.264 to 0.820) and 0.577 (from 0.102 to 0.855) 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 2nd chromosome of Liangshan semi-fine wool sheep was constructed by Crimap (2.4). The complete length of the map was 337.4cM, which had an average marker interval of 42.2cM as well as the maximum and minimum interval of 59.7cM (OarCP0079~OarFCB20) and 25.8cM (OarFCB20~BMS1126). Besides that, the sequence of loci was coincident with the USDA-MARC and SM4.2 (ARKdb) ovine map, however most marker intervals were larger than the latter two.Phenotypes of five traits were handled statistically by SAS6.12 in the 184 progenies. The "CORR" consequence revealed the significant correlation between WW and WDG, WDG and 18W, WDG and 30W, WW and 18W, WW and 30W. Meanwhile, the "GLM" result demonstrated sire factor only has robust influence on BW.QTL mapping was accomplished through interval mapping. A couple of software (QTL Express and WinQTLcart), which employ different methods (regression and LR test) separately, were applied to analyze simultaneously. In family H1G4035, a putative QTL affecting BW was detected between BM2626 and OarFCBll both by QTL Express and WinQTLcart, which was similar to the QTL on bovine genome reported by M.D. Gross and M.D. MacNeil (2001) .The locus positions generated by both of software were extremely closed to BMS2113 (smaller than lcM). In addition, a QTL that has great effect on WDG was observed merely by WinQTLcart in the same family, situating in the interval of BM2113 and OarFCBll. Therefore, the fragment around BMS2113 has the probability of tightly relating to the traits involving early body development.
|
PDF Full Text Request