中国荷斯坦牛PIN1基因对产奶性状的遗传效应分析

前期研究通过荷斯坦公牛全基因组重测序鉴定到17个奶牛产奶性状候选功能基因,其中,肽基脯氨酸顺反异构酶基因(PIN1)参与甘油三酯代谢、甘油磷脂代谢以及mTOR信号通路,且位于产奶量和乳蛋白量性状QTL区间。为进一步系统分析PIN1基因是否对奶牛产奶性状具有遗传效应,本实验基于40头公牛的基因组DNA混池,采用PCR产物直接测序法对PIN1基因的全部编码区以及上下游调控区2000 bp进行扫描,在内含子2检测到1个SNP位点7:g.14432394G>A,A、G等位基因频率分别为0.4797和0.5203。采用靶向测序基因型技术对北京地区987头中国荷斯坦母牛进行个体基因型检测,对SNP位点7:g.14432394G>A与5个产奶性状进行关联分析。结果表明:在第1泌乳期,SNP 7:g.14432394G>A与产奶量、乳脂量、乳蛋白量和乳蛋白率呈显著或极显著关联(P=0.0001~0.0493);在第2泌乳期,SNP与产奶量、乳脂量、乳脂率和乳蛋白量呈显著或极显著关联(P=0.0001~0.0104);SNP位点7:g.14432394G>A对产奶量、乳脂量、乳蛋白量和乳蛋白率的加性效应或等位基因替代效应均达到显著或极显著。综上,PIN1基因对中国荷斯坦牛的产奶量和乳蛋白、乳脂性状具有显著遗传效应,可作为遗传标记用于基因组选择,以加快遗传进展。

Identification of Genetic Effects of PIN1 Gene with Milk Production Traits in Chinese Holstein Cattle

Our pervious study has identified 17 functional genes for milk composition traits by performing whole genome resequencing of the Holstein bulls.One of them,the PIN1 gene is involved in glycerolipid,glycerophospholipid metabolisms and mTOR signaling pathway,but also is located within the known QTL region for milk yield and protein yield.The purpose of the present study was to further verify whether the PIN1 gene has signi?cant genetic effect on milk production traits in dairy cattle.By resequencing the entire exons and 2 kb of 5’and 3’flanking region,one SNP,namely 7:g.14432394G>A,was identi?ed in the intron 2 of PIN1.The frequency of allele A and G was 0.4797 and 0.5203,respectively.With target sequencing technology,a total of 987 Chinese Holstein cows were individually genotyped on this SNP.Association analysis between the SNP and five milk traits was implemented with mixed animal model.As a result,we found that SNP 7:g.14432394G>A was significantly associated with the milk yield,fat yield,protein yield and protein percentage in the first milk lactation(P=0.0001~0.0493).Also,significant associations were revealed between SNP 7:g.14432394G>A and milk yield,fat yield,fat percentage and protein yield in the second milk lactation(P=0.0001~0.0104).Correspondingly,the additive and substitution effects of this locos on milk yield,fat yield,protein yield and protein percentage were significant as well.Therefore,our findings indicated that the PIN1 gene has signi?cant genetic effects on milk yield and milk composition traits and provide a potential molecular marker for the genomic selection program in dairy cattle.