Microsatellite DNA Polymorphism For Gansu Pig Breed Resources

Nine pairs of microsatellite primers selected from the FAO/ISAG panel of pig primers were used to genotype 273 samples of seven Gansu pig breeds (lines), including Hezuo pig, Huate A, Huate B, Duroc, Landrace, Yorkshire and Pietrain. Genetic variation within and and relationshipa between the breeds (lines) were assessed using gene frequency, genetic heterozygosity, polymorphic information content, and NJ and UPGMA phylogenetic trees constructed using Nei's Standard genetic distances. It is expected that the information on genetic variation of Gansu pig genetic resouces at molecular level could be taken into account as a baseline for the conservation and rational utilization of the pig genetic resources, and genetic improvement and development of the new lines using selection and crossbreeding in Gansu. The results indicated that:1. At the nine microsatellite loci, 131 alleles were detected with eight or more alleles at each locus, including a high polymorphism present at all the loci.2. The average heterozygosities of seven breeds or lines varied from 0.7427 to 0.8109 with the Pietrain being the lowest and the Yorkshire the highest. The average polymorphic information content was also high, ranging between 0.6820 and 0.7807. These indicated that the genetic variation within all breeds or lines were considerably high, it is still possible to improve the foreign breed via selection. However, the Huate A, Huate B and Hezuo pig were erosed by the exotic genetics and there is a need to purify their genome. A limited number of Pietrain in Gansu explained its low genetic variation among the breeds or lines.3. The Huate B line was close to Yorkshire but the Hezuo pig was distant from other six breeds or lings.4. The phylogenetic trees showed that the Yorkshire, Pietrain and Duroc were in a single cluster, Landrace and Huate B in another cluster, Huate A in a separate, third cluster, and Hezuo pig in a unique cluster.5. Gansu pig genetic resources have been erosed by exotic genetics; therefore specific actions have to been taken for the conservation of the unique resources.