Construction Of The Linkage Mapping And QTL Identification For Meat Trait On Chr.2 And 4 In Swine

Because of pursuing the lean pork meat, it resulted in the decreasing of meat quality and economic losses in swine industry. Now, people tend to be interested in meat quality when the standard of living has been increased. Meat quality are quantitative trait and affected by polygene. The measurement of meat quality was complicate and only done after slaughtered. Therefore, these factors limited the application of traditional breeding. The development and application of genetic markers provided a chance to solve this problem. An experimental population based on a cross between lines or breeds that differ markedly for one or more traits of interests could be used to detection and localization of quantitative trait loci(QTL). According to this, a three-generation reference family in our university were established by using three Large White and seven Chinese Meishan pigs for gene mapping and QTL identification. About 147 F2 offspring had been slaughtered and their meat quality trait were measured and scored. Fourteen microsatellite loci on chromosome 2 and 4 were chosen and used to genome scanning. They were: sw2404, sw1201, s0170, sw1883, swl879, sw2192 and sw308 on chromosome 2; sw2404, sw835, sw752, sw270, sw841, sw445 and s0161 on chromosome 4. The genetic linkage map of chromosome 2 and 4 were constructed with CRI-MAP software. By using the least-square analysis, several QTLs were identified and localized on chromosome 2 and 4. The results as follows:1. By using CRI-MAP software, the linkage map of chromosome 2 and4 with the length of 192.5cM and 158.2cM, respectively,, were constructed. Compared with the published map of USDA-MARC, the orders of loci were insistent, the interval of loci in our linkage map were longer.2. A QTL affecting the intramuscular fat(IMF)(P<0.01) was detected on chromosome 2 using the phenotype data of 2000 year. When we did to tergether the phenotype data of 1998 year, the QTL was still present.3. A QTL affecting meat water was identified on chromosome 4 using the phenotype data of 1998. When we added the phenotype data of 2000, F-ratio did not reach the chromosome significant value.These results showed that our genetic linkage map was correct and could be used to localization of QTL. The result of QTL mapping should be confirmed, with further research.