Studies On The Genetic Structure And The Origin And Domestication Of Jinhua Swine

In this paper, we have detected the genotypes of 65 microsatellite loci by the fluorescent primers in Jinhua subpopulations:Lineâ… ,Lineâ…¡, Lineâ…¢and Jiaxing, Shengxian, Meishan, Erhualian and Landrace.Base on the genotype, we analyzed the genetic structure of Jinhua subpopulation and genetic diversity among Jinhua pig as well as the other breeds.Moreover we calculated the genetic distance among Jinhua and other breeds.There are 1260 alleles on the 65 loci of Jinhua 271 samples of 3 populations.In Jinhua population, Line I has the highest average number of effective allele (Ne=3.49), Lineâ…¡(Ne-2.81) and Lineâ…¢(Ne=2.49).The average of polymorphism information content (PIC) in each subpopulation is above 0.5,Lineâ…¢has the highest value:PIC=0.586, followed by Line I PIC=0.558 and Lineâ…¡PIC=0.514.On the average heterozygosis, Lineâ… is 0.3811,Lineâ…¡is 0.3992 and Lineâ…¢is 0.4415.By the Hardy-Weinberg equilibrium test, Lineâ… deviates from it more and behinded is Lineâ…¢,Lineâ…¡deviates from it less.The genetic differentiation shows that the differentiation between Jinhua Lineâ…¢and Lineâ…¡is small (F=0.1883),both of them with Jinhua Lineâ… has a big F values (0.3663,0.3619 respectively).The genetic differentiation of all Jinhua subpopulations with Shengxian pig is the highest (F=0.4499,0.4654 and 0.4801 respectively), and with medium Meishan pig is the least (F=0.3581,0.356 and 0.3572 respectively).The genetic distance between Jinhua pig and others show that Jinhua pig far away from abroad breeds except Large white and Jinhua line I has a closed genetic distance with Xiang (Da=1.2106) and Large white breeds (Da=1.1322).Above all,there is some degree of inbred accumulation and many alleles are losted in Jinhua subpopulations, furthermore,all subpopulations were affected by genetic drift. We also analysed the effect of microsatellite IGF1 on growth traits in Jinhua pig. Significant effect was found for microsatellite locus IGF1 genotype on BW (P<0.05),with positive effects associated with the 286/286 genotype, and 280/286 genotype on LWB in second parity (P<0.05). Furthermore, according to analysis of allele average substitution effect, alleles 274bp and 286bp was favourable for BW increase, allele 280bp was favourable for LWB increase in the second parity.By correlation analysis, total number of birth, number of birth alive and LWB of the second parity in jinhua pig had highly significant correlation(P<0.01), therefore increasing LWB of the second parity could improve litter performance of Jinhua pig. Therefore, microsatellite could be a useful MAS molecular marker for Jinhua pig breeding. And we mapping a meat quality candidate gene SIM1 with SW781 and SW301 By IMpRH panel to chromosome 1p13 in porcine.In addition, mtDNA D-loop sequence was used as molecular marker to analyze the phylogenetic relationship, construction and distribution of haplotypes on 92 breeds that including 68 samples of Chinese domestic pigs, in order to understand the origin and domestication of Chinese pigs from matrilineal and also the evolution of Jinhua pig.Complete mitochondrial DNA D-loop sequences were determined for 68 Chinese pigs.Comparisons of these sequences revealed 66 haplotypes.We combined the phylogenetic analyses results from software Mega and NETWORK of Chinese domestic breeds with history of archaeology, microsatellite and Y chromosome evidences,from matrilineal we suppose that:1.Chinese pigs and Europwan pigs have a common maternal ancestor.2.It is different on origin between north and south of Chinese breeds,Yellow River is a boundary and north breeds origin from wild boar in northeast China, south breeds origin from Zhejiang wild boar, probably.There is a domestication aggregation area in the Yangtze River mid-downstream drainage basin, and it has two domestication centres, which have mutil-level.Zhejiang and Jiangxi provinces may be the biggest domestication centres of Chinese breeds and the origin of south pigs.4.Jinhua subpopultions have different origin and domestic history, Lineâ…¡has ancient maternal pedigree moreover Lineâ… and Lineâ…¢in the same domestication centra.5.Base on the results of phylogenetic relation and haploid net structure, we believe that the reason of many alleles are losted in Jinhua subpopulations is Jinhua subpopulations have different domestic history.