The genomics of fat and fertility in pigs

二十年来，商品猪群体的选择压力以脂肪积累为代价提高了蛋白质沉积的效率。体脂的减少伴随着青春期推迟，产仔数减少，仔猪断奶后恢复发情的时间更长。这一建议是为了检验这样一种假设，即猪主要或仅在脂肪组织中表达的基因是繁殖性状的多态遗传标记，并调节繁殖过程。我们的总体目标是确定脂肪相关基因和基因产物对猪繁殖性能的影响和机制。这些结果将为提高生育力的遗传选择提供标记，并深入了解脂肪在调节生殖中的作用。我们将在脂肪组织垫中识别预测生殖性状的基因组标记，包括青春期、产仔数和断奶至发情间隔。我们将从已知繁殖表型的&gt；3000头猪的多世代DNA库中筛选对遗传选择有用的多态。我们将用已知的脂肪基因、我们之前基因发现工作中的未知基因以及与生殖性状相关的染色体区域的基因进行筛选。我们将进一步比较生育能力提高的猪的种群(&gt；16/窝)和低生育能力的猪群(&lt；9/窝)，以建立生殖特征以及已知和新的候选基因在脂肪和生殖组织中的表达谱。我们将通过对卵巢、子宫和胚胎的研究来确定变异生育的基础。我们将检测皮下和内脏脂肪库中的基因表达，以寻找与多产相关的脂肪。另一个目标是确定皮下和内脏脂肪基因产品对猪繁殖性状的影响。这些研究将利用重要的终点，包括表明排卵的卵巢变化，胚胎发育到囊胚期，以及胚胎与子宫的附着。这一多方面的项目将产生关于猪繁殖的遗传学和功能基因组学的新信息，对养猪业和加拿大都有价值。

Over two decades, selection pressure in commercial pig populations has improved the efficiency of protein deposition at the expense of fat accumulation.  Reduction in body fat has been accompanied by later puberty, reduced litter size and a longer period for return to estrus after piglets are weaned. This proposal has been developed to test the hypothesis that genes expressed predominantly or exclusively in adipose tissue in the pig serve as polymorphic genetic markers of reproductive traits and regulate reproductive processes. Our overall objective is to determine the influence and the mechanisms of adipose-associated genes and gene products on reproductive performance in swine. The results will provide markers for genetic selection to improve fertility, along with insight into the role of fat in modulation of reproduction.  We will identify genomic markers in adipose tissue mat predict reproductive traits, including puberty, litter size and weaning to estrus interval. A multigenerational DNA bank derived from >3000 pigs of known reproductive phenotype will we screened for polymorphisms useful for genetic selection. We will screen with known adipose genes, with unknown genes derived from our previous gene discovery efforts, and with genes from regions of chromosomes associated with reproductive traits.  We will further compare populations of pigs of elevated fertility (>16/litter) with subfertile populations (<9/litter) to establish reproductive characteristics and expression profiles of known and novel candidate genes in adipose and reproductive tissues. We will determine the bases for variant fertility by studies of the ovary, uterus and embryo. We will examine gene expression in subcutaneous and visceral fat depots to seek adipose correlates to prolificity. A further goal is to determine the effects of subcutaneous and visceral adipose gene products on pig reproductive traits. These studies will employ important endpoints including ovarian changes indicative of ovulation, embryo development to the blastocyst stage, and attachment of the embryo to the uterus.   This multifaceted project will yield new information on the genetics and functional genomics of pig reproduction valuable to the pig industry and to Canada.