Lonergan S M, Ernst C W, Bishop M D, Calkins C R, Koohmaraie M
Roman L. Hruska U.S. Meat Animal Research Center, ARS, USDA, Clay Center, NE 68933-0166, USA.
J Anim Sci. 1995 Dec;73(12):3608-12. doi: 10.2527/1995.73123608x.
Restriction fragment length polymorphisms (RFLP) have been identified at the bovine calpastatin locus. The objective of the present study was to determine whether these polymorphisms are related to variations in calpastatin activity or beef tenderness in unrelated animals of mixed breeding. A sample of 83 crossbred steers from sires representing eight different breeds was examined to determine this relationship. A 2.2-kb cDNA coding for domains 2 through 4 plus a 3' untranslated region of bovine skeletal muscle calpastatin was used as a probe for calpastatin RFLP. Polymorphisms were found using the restriction enzymes BamHI and EcoRI. Polymorphic restriction fragments for BamHI were 9.0 and 5.0 kb and for EcoRI were 6.0 and 4.0 kb. Allelic frequencies for BamHI restriction fragments were .53 for the 9.0-kb allele and .47 for the 5.0-kb allele. Allelic frequencies for EcoRI restriction fragments were .43 for the 6.0-kb allele and >57 for the 4.0-kb allele. No polymorphisms were identified using the restriction enzymes BglII, DraI, or PstI. No associations between EcoRI and BamHI RFLP and 24-h calpastatin activity of Warner-Bratzler shear force at 14 d postmortem were detected. Therefore, the polymorphic EcoRI and BamHI restriction sites within the bovine calpastatin locus do not detect DNA sequence differences responsible for variation in calpastatin activity or tenderness of aged beef. Therefore, these polymorphisms cannot be used to predict tenderness of aged beef from unrelated animals of mixed breeding. These results do not exclude the possibility that other DNA sequences in or near the bovine calpastatin gene are responsible for variation in calpastatin activity or meat tenderness. The lack of a relationship between these calpastatin RFLP and meat tenderness must be distinguished from the well-documented relationship between calpastatin activity and meat tenderness. Therefore, further development of calpastatin-based methods for predicting beef tenderness in unrelated animals of mixed breeding should focus on basic factors influencing calpastatin activity at the molecular and cellular level.
在牛的钙蛋白酶抑制蛋白基因座上已鉴定出限制性片段长度多态性（RFLP）。本研究的目的是确定这些多态性是否与混合育种的非亲缘动物中钙蛋白酶抑制蛋白活性或牛肉嫩度的变化有关。对来自代表八个不同品种的公牛的83头杂交阉牛样本进行了检测，以确定这种关系。编码牛骨骼肌钙蛋白酶抑制蛋白第2至4结构域加上3'非翻译区的2.2kb cDNA用作钙蛋白酶抑制蛋白RFLP的探针。使用限制性内切酶BamHI和EcoRI发现了多态性。BamHI的多态性限制性片段为9.0kb和5.0kb，EcoRI的多态性限制性片段为6.0kb和4.0kb。BamHI限制性片段的等位基因频率，9.0kb等位基因为0.53，5.0kb等位基因为0.47。EcoRI限制性片段的等位基因频率，6.0kb等位基因为0.43，4.0kb等位基因为>0.57。使用限制性内切酶BglII、DraI或PstI未鉴定出多态性。未检测到EcoRI和BamHI RFLP与死后14天的Warner-Bratzler剪切力的24小时钙蛋白酶抑制蛋白活性之间的关联。因此，牛钙蛋白酶抑制蛋白基因座内的多态性EcoRI和BamHI限制性位点未检测到导致钙蛋白酶抑制蛋白活性或老龄牛肉嫩度变化的DNA序列差异。因此，这些多态性不能用于预测混合育种的非亲缘动物老龄牛肉的嫩度。这些结果并不排除牛钙蛋白酶抑制蛋白基因内或附近的其他DNA序列导致钙蛋白酶抑制蛋白活性或肉嫩度变化的可能性。必须将这些钙蛋白酶抑制蛋白RFLP与肉嫩度之间缺乏相关性与钙蛋白酶抑制蛋白活性与肉嫩度之间有据可查的关系区分开来。因此，基于钙蛋白酶抑制蛋白的预测混合育种非亲缘动物牛肉嫩度方法的进一步发展应侧重于在分子和细胞水平上影响钙蛋白酶抑制蛋白活性的基本因素。
