Study Of Herd Genetic Structure And Microsatellite Marker Of Economic Traits On Seghers Pigs

This experiment studied the Seghers 5-line-crossbreed commercial hybrid line by using microsatellite DNA genetic markers. 5 grand-grandparent lines (line A, line B, lien C, line X, line Y), grandparent herd, parent herd and the final result commercial hybrid herd were studied. The herd genetic structures, genetic diversity and the distance among herds were analyzed. The relationship between genetic marker genotype of Seghers herds and economic traits were analyzed. The results of the experiment were shown as follows. 37 alleles were detected at loci S0214, S0003, SW790 and SWR485 with average 9.3 alleles per locus. The numbers of alleles in each grand-grandparent line herds were different from each other. There were great genotype differences among grand-grandparent herds. This indicated that the genetic background of 5 grand-grandparent lines were different from each other. The characteristic bands of Seghers grand-grandparent pigs were found. The characteristic bands of line A were 154bp band at locus SW790 and 126bp band at locus SWR485. The characteristic bands of line B were 116bp band at locus SW790 and 143bp, 146bp, 161bp bands at locus S0003. The characteristic band of line X was 138bp band at locus SWR485.The range average locus heterozygosity of grand-grandparent herds, grandparent herd, parent herd, and commercial hybrid herd was between 0.6795 and 0.7689. The locus average polymorphism information content was between 0.6786 and 0.7686. The result above showed that the genetic diversity of Seghers herds at these loci was high, which because the genetic breeding backgrounds of Seghers pigs were enough wide. The average locus heterozygosity of grandparent herd, parent herd and commercial hybrid herd rose gradually with the decline of herd position in the hybrid system. The clustering of 5 grand-grandparent lines was done using group average method based on the Nei's standard distance. Line A and line X herds which only female pigs were used, met into one group. Line C and line Y which only male pigs were used met into one group. The result accorded with the effect of the lines in the hybrid system. It was analyzed the relationship between the microsatellite marker genotypes and traits, which included back fat thickness, whole period daily gain, ejaculation volume, sperm density, sperm livingness, the litter size, alive Utter size, litter weight, 21 day litter weight, 28 day litter weight. The genetic marker genotypesof the traits at each locus were found. The results were shown as follows. The genetic marker genotype of back fat thickness was genotype AA at locus SWR485. The genetic marker genotype of the whole period daily gain was genotype AA at locus SW790. The genetic marker genotypes of the ejaculation volume were genotype AA at locus S0003, genotype AA at locus SW790. The genetic marker genotype of the sperm density was genotype AA at locus SWR485. The genetic marker genotypes of the sperm livingness were genotype AA at locus S0003 and genotype CC at locus SW790. The genetic marker genotype of the litter size was genotype BB at locus S0003. The genetic marker genotypes of the litter weight was genotype AA at locus S0003. The genetic marker genotype of the 21st day litter weight was genotype BB at locus S0003.