微卫星标记对杂种优势研究杂交猪群的遗传评价

摘要

从猪的4、6、7、8和13号染色体上选取了39个微卫星位点,在大白(Y,n=34)、长白(L,n=46)、梅山(M,n=55)、大白×长白(YL,n=32)、长白×大白(LY,n=36)、大白×梅山(YM,n=82)和梅山×大白(MY,n=47)7个实验猪群中,评定了猪群的分子遗传特征,分析了标记位点对3个性状(初生重,BWT;平均日增重,ADG;料肉比,FMR)杂种优势的遗传效应.结果表明,观察到的等位基因数范围是2～6个,平均是4.13个;观察杂合度在0.39(Y)和0.58(YM+MY)之间;平均有效信息含量(PIC)在0.33(Y)到0.5(YM)之间.在大白和长白中,有两个位点(sw2155and sw1037)的等位基因呈固定状态,而在梅山中,有3个位点(sw2409,sw2454and sw1691)的等位基因呈固定状态.杂合度和亲缘关系分析结果,揭示了7个群的内在遗传关系.标记位点对杂种优势的遗传效应分析结果表明,在F1代两种不同杂交组合中,存在若干个对3种性状杂种优势有显著意义的标记位点(P≤ 0.01),如对BWT有s0161,swr1130和sw1856;对ADG有sw1856和swr2036;对FMR有swl302和swr2036.这些有意义标记位点,蕴含与杂种优势有深刻的遗传关系.%The molecular genetic characteristics were evaluated, and the genetic effects of marker loci on heterosis of three traits(Birth weight, BWT; Average daily gain, ADG; Feed and meat ratio, FMR ) were analyzed in the experimental pig populations, Yorkshire (Y,n =34), Landrace (L,n =46) and Meishan (M,n =55); Yorkshire×Landrace (YL,n =32) and its reciprocal (LY,n =36), Yorkshire× Meishan (YM,n =82) and its reciprocal (MY, n =47), by 39 microsatellite marker selected from chromosomes of SSC4, 6, 7, 8 and 13. The results indicated that observed alleles ranged from 2 to 6, average 4.13, observed heterozygosity varied from 0.39 (Y) to 0.58 (YM+MY) and average polymorphism information content (PIC) varied from 0.33 (Y) to 0.5 (YM). There were two loci (sw2155 and sw1037) at which the alleles were fixed in Y and L, and there were three loci (sw2409, sw2454 and sw1691) at which the alleles were fixed in M. The results from heterozygosity and kinship analysis revealed intrinsic genetic relationship among the seven populations. Furthermore, the results on genetic effect analysis indicated that several marker loci had significant effect on heterosis of the three traits in the two different F1 crossbred populations (P ≤ 0.01), such as s0161, swr1130 and sw1856 for BWT, sw1856 and swr2036 for ADG, and sw1302 and swr2036 for FMR. The significant marker loci implied the deep genetic relationship between molecular marker loci and heterosis.