US Meat Animal Research Center, Clay Center, NE 68933, USA.
J Anim Sci. 2011 Sep;89(9):2663-72. doi: 10.2527/jas.2010-3556. Epub 2011 Mar 31.
The identification of predictive DNA markers for pork quality would allow US pork producers and breeders to select genetically superior animals more quickly and efficiently for the production of consistent, high-quality meat. Genome scans have identified QTL for tenderness on SSC 2, which have been fine-mapped to the calpastatin locus. The objectives of this study were to identify the sequence variation in calpastatin that likely affects tenderness in commercial-level pig populations and to develop definitive DNA markers that are predictive of pork tenderness for use in marker-assisted selection programs. We resequenced the calpastatin regulatory and transcribed regions in pigs with divergently extreme shear force values to identify possible mutations that could affect tenderness. A total of 194 SNP were identified in this sequence, and 31 SNP were found in predicted transcription factor binding sites. We tested 131 polymorphisms in our research population and a subset (40) of these in samples of industry pigs for their association with objective measures of tenderness. We identified 4 SNP that were consistently associated with pork tenderness in all the populations studied, representing 2,826 pigs from 4 distinct populations. Gel shift assays were designed for these SNP and 12 other polymorphic sites. Six sites demonstrated a gel shift when probes were incubated with nuclear extract from muscle, heart, or testis. Four of these sites, a specificity protein 1 (Sp1) site around nucleotides 12978 and 12979, a potential thyrotroph embryonic factor (Tef) site at nucleotide 25587, an unknown site at nucleotide 48699, and myocyte enhancer factor-2 (Mef-2)/TATA sites with SNP at positions 49223 and 49228 were allele specific in binding nuclear proteins. The allele frequencies for the tender alleles were similar (0.11 to 0.36) in the 4 different commercial populations. These 4 SNP were not in complete linkage disequilibrium with each other and may independently affect calpastatin expression, tenderness, or both. These markers should be predictive of pork tenderness in industry populations.
用于猪肉品质的预测性 DNA 标记的鉴定将使美国猪肉生产者和饲养者能够更快、更有效地选择具有遗传优势的动物，以生产一致的高质量肉类。基因组扫描已经确定了 SSC2 上与肉质嫩度相关的 QTL，并已精细定位到钙蛋白酶抑制因子（calpastatin）基因座。本研究的目的是鉴定可能影响商业猪群肉质嫩度的钙蛋白酶抑制因子序列变异，并开发可预测猪肉嫩度的明确 DNA 标记，用于标记辅助选择计划。我们对剪切力值差异极大的猪进行了钙蛋白酶调控区和转录区的重测序，以鉴定可能影响嫩度的潜在突变。在该序列中鉴定出 194 个 SNP，其中 31 个 SNP 位于预测的转录因子结合位点。我们在研究群体中测试了 131 个多态性，并在来自 4 个不同群体的工业猪样本中测试了其中 40 个多态性，以确定它们与嫩度的客观测量的相关性。我们在所有研究的群体中都鉴定出了 4 个 SNP，这些 SNP 与猪肉嫩度始终相关，代表了来自 4 个不同群体的 2826 头猪。凝胶阻滞试验设计用于这些 SNP 和其他 12 个多态性位点。当用肌肉、心脏或睾丸核提取物孵育探针时，有 6 个位点发生了凝胶阻滞。这 6 个位点中有 4 个位于核苷酸 12978 和 12979 周围的特异性蛋白 1（specificity protein 1，Sp1）位点、核苷酸 25587 处的潜在甲状腺细胞原胚因子（thyrotroph embryonic factor，Tef）位点、核苷酸 48699 处的未知位点、位于 SNP 位置 49223 和 49228 的肌细胞增强因子-2（myocyte enhancer factor-2，Mef-2）/TATA 位点，这些位点在与核蛋白结合时具有等位基因特异性。在 4 个不同的商业群体中，嫩等位基因的等位基因频率相似（0.11 至 0.36）。这 4 个 SNP 彼此之间不完全连锁不平衡，可能独立地影响钙蛋白酶抑制因子的表达、嫩度或两者兼而有之。这些标记应该可以预测工业群体中猪肉的嫩度。
