【作者】 孙延晓；

【导师】 曾勇庆；

【作者基本信息】 山东农业大学 ， 动物遗传育种与繁殖， 2008， 硕士

【摘要】 猪产仔数的遗传力低,用常规育种方法进行选择收效甚微。所以寻找其主效基因和遗传标记对提高猪产仔数具有重要意义。动物的整个繁殖过程包括生殖细胞生成和成熟、射精、排卵、妊娠和泌乳等各个环节,每一环节都受生殖激素的控制。因此,编码这些生殖激素或其受体的基因是繁殖性能遗传标记最为理想的候选基因。本研究选择催乳素受体(prolactin receptor,PRLR)基因和视黄醇结合蛋白4(retinol-binding protein 4, RBP4)基因为候选基因,采用PCR-RFLP方法,对莱芜黑猪、鲁莱黑猪、里岔黑猪、鲁烟白猪、新沂蒙黑猪5个山东地方/培育猪种和大约克夏、长白、杜洛克3个引进猪种共八个猪种323头繁殖母猪进行PRLR和RBP4基因的多态性检测,并采用最小二乘法分析其对产仔数的遗传效应,进而分析其对母猪多产性(总产仔数、产活仔数)的影响。本研究的主要主要结果如下:对于PRLR基因,在莱芜黑猪、里岔黑猪、鲁莱黑猪、长白猪、大约克夏猪的优势等位基因是B(都在0.5以上),基因型频率是AB>BB>AA;而新沂蒙黑猪、鲁烟白猪和杜洛克猪中优势等位基因是A,AA基因型频率显著高于BB基因型频率(P<0.05),其中杜洛克猪A等位基因频率最高,为0.8000。经X2检验,各群体基因型分布没有显著偏离哈代-温伯格平衡(P>0.05)。PRLR基因对产仔数性状的影响均为显著(P<0.05),在山东地方/培育猪种内,PRLR基因AA型母猪的总产仔数和产活仔数比BB型母猪平均多产1.03头和0.89头(P<0.05),引进猪种中AA型母猪比BB型母猪平均多产分别为1.26头和1.11头(P<0.05)。对于RBP4基因,三个引进猪种和两个山东地方/培育猪种(新沂蒙黑猪、鲁烟白猪)的基因型以AA型出现的频率高,优势等位基因为A(在0.6以上),杜洛克猪的A等位基因的频率最高,为0.8462。在另外三个山东地方/培育猪种(莱芜黑猪、里岔黑猪和鲁莱黑猪)中基因型频率均呈现AB﹥BB﹥AA的趋势,优势等位基因为B。经X2检验,各群体基因型分布没有显著偏离哈代-温伯格平衡(P>0.05)。对产仔数性状的影响,在山东地方/培育猪种内,RBP4基因AA型母猪的总产仔数和产活仔数比BB型母猪平均多产0.59头和0.51头,引进猪种中AA型母猪比BB型母猪平均多产分别为0.72头和0.64头(P<0.05)。PRLR和RBP4基因对母猪初产产仔数的影响高于经产。其中,对于初产母猪,PRLR基因AA型比BB型的总产仔数高1.25头,产活仔数高1.13头, RBP4基因AA型比BB型相应的高0.79头和0.72头;而对于经产母猪,PRLR基因AA型比BB型的总产仔数高0.87头,产活仔数高0.82头,RBP4基因AA型比BB型相应的高0.58头和0.42头。合并基因型AAAA的母猪要比BBBB合并基因型母猪的初产总产仔数和产活仔数分别多1.98头/胎和1.80头/胎,而经产总产仔数和产活仔数分别多1.39头/胎和1.19头/胎。合并基因型对多产性的影响无明显规律,其对多产性的遗传效应不是各个基因型效应的简单相加,但合并效应稍高于单个基因型效应。本研究中PRLR、RBP4基因对所研究猪种的产仔数性状的效应明显,遗传多态性丰富,其中PRLR基因比RBP4基因的遗传效应略大,可以为探讨利用标记辅助选择方法改进猪的产仔数性状进一步提供技术方法和策略,从而提高猪的繁殖性能。更多还原

【Abstract】 Because of its very low heritability of litter size of pig, the improvement of the litter size is limited by the conventional breeding technology. It is very important to find the major genes and the genetic markers related to the litter size. All reproductive pathways of animal will be mediated by procreant hormones, including generation and maturation of procreant cells, ejaculation, ovulation, pregnancy, secretion of milk and so on. Hence genes, which coding procreant hormones or their receptors, are presumed to be ideal candidate genes for reproductive traits. In this experiment, 323 pigs including Laiwu Black, Lulai Black, Licha Black, Luyan White, New Yimeng Black, Yorkshire, Landrace and Duroc were selected to detect genetic variants of PRLR and RBP4 genes by PCR-RFLP. According to the genotypic frequency of these two genes, we calculated the allelic frequency in each pig breeds. And the genetic effects of the genes on litter size were also analyzed by the least square analysis. Gathering the litter size data of examined pigs, including the total number of born (TNB) and the number of born alive( NBA), we analyze the effects of them on prolificacy, The main results are asfollows:For PRLR gene, In Laiwu Black, Licha Black, Lulai Black, Landrace and Yorkshire, the preponderant alleles is B allele, the genotype frequency was AB>BB>AA. In New Yimeng Black, Luyan White and Duroc, the preponderant alleles was A allele, the frequency of AA genotype was significantly higher than the frequency of BB genotype(P<0.05),among this three pig breeds, the frequency of the allele A was highest in Duroc (0.8000). The results of Chi square showed that, all the eight pig breeds populations fitted the H-W equilibrium situation(P>0.05). In Shandong local breeds, the average TNB and NBA of AA was 1.03 and 0.89 more than that of BB, while 1.26 and 1.11 more than BB in the foreign pig breeds respectively, and the effect of the genotype on reproduction traits was significant (P<0.05).For RBP4, the frequency of AA genotype was higher than the other two genotype frequency in the three foreign pig breeds and two shandong local breeds(New Yimeng Black, Luyan White), and the preponderant allele was A, among these pig breeds, the frequency of the allele A was highest in Duroc (0.8462). While, in the other three Shandong local breeds, the genotype frequency was AB>BB>AA, and the preponderant allele was B. The results of Chi square showed that, all the eight pig breeds populations fitted the H-W equilibrium situation(P>0.05). In Shandong local breeds , the average TNB and NBA of AA was 0.59 and 0.51 more than that of BB, while 0.72 and 0.64 more than BB in the foreign pig breeds respectively(P<0.05).The Effects of PRLR and RBP4 of litter sizes in the first parity was higher than those in the later parities.For the first parity , AA genotypic sows of PRLR produced 1.25 TNB and1.13 NBA more than BB genotypic sows, AA genotypic sows of RBP4 produced 0.79 TNB and 0.72 NBA more than BB genotypic sows.While, for the later parities, AA genotypic sows of PRLR produced 0.87 TNB and 0.82 NBA more than BB genotypic sows, and AA genotypic sows of RBP4 produced 0.58 TNB and 0.42 NBA more than BB genotypic sows.the TNB and NBA of the combined genotype BBBB was 1.98 and1.80 more than those of AAAA in the first parity, while 1.39 and 1.19 more than in the later parities respectively (P<0.05). The effects of combined genotypes of PRLR and RBP4 have no obvious law. Its genetic effects on prolificacy are not simply the multiplications of every genotype. But its effect of combined genotypes was higher than the effect of individual genotype.In this research, the effects of PRLR and RBP4 on prolificacy was proved to be obvious, and they were abundant in polymorphism. From these results we can putatively drew the conclusion that these two genes could be used to select the high reproduction traits of pigs with molecular markers assisted selection programs, in order to improve the level of prolificacy.更多还原