Effect and mode of action of the Texel muscling QTL (TM-QTL) on carcass traits in purebred Texel lambs.
Effect and mode of action of the Texel muscling QTL (TM-QTL) on carcass traits in purebred Texel lambs.
复制标题
DOI：
10.1017/s1751731114001104
复制
发表时间：
2014-07
期刊：
影响因子：
--
通讯作者：
J. Macfarlane;N. Lambe;Oswald Matika;P. Johnson;B. Wolf;W. Haresign;Stephen Bishop;L. Bünger
中科院分区：
文献类型：
--
作者：
J. Macfarlane;N. Lambe;Oswald Matika;P. Johnson;B. Wolf;W. Haresign;Stephen Bishop;L. Bünger
TM-QTL是位于绵羊第18号染色体上的一个数量性状位点（QTL），已知影响特克塞尔羊的腰部肌肉生长。以前的研究表明，它的遗传模式与父系极性超显性一致，但这尚未得到正式证明。本研究使用纯种特克塞尔羊分离TM QTL，以确认其存在的染色体区域中，它是第一次报告，并确定其遗传模式。为此，本研究使用了来自Texel羊群的第一批可用数据，其中包括纯合子TM-QTL携带者（TM/TM; n=34）以及纯合子非携带者（+/+; n=40）和从其父系（TM/+; n=53）或其母系（+/TM; n=17）遗传TM-QTL的杂合子TM-QTL携带者。表型包括广泛的腰部肌肉，胴体组成和组织分布性状。在OAR 18上存在影响超声肌肉深度的QTL，父本QTL效应范围为+0.54至+2.82 mm UMD（s.e. 0.37至0.57 mm）。测量腰肌宽度、深度、面积、腰肌体积和解剖M。TM/+组羔羊的腰最长肌重量显著高于+/+组羔羊（+2.9%~+7.9%; P<0.05）。TM-QTL对各肌肉性状的效应均为父本极性超显性（P<0.05）。相比之下，TM-QTL对20周龄的活重和胴体重均存在加性效应; TM/TM动物显著（P<0.05）比+/+（分别为+11.1%和+7.3%）和+/TM动物（分别为+11.9%和+11.7%）重，TM/+居中。腿，鞍和肩部区域的重量（校正胴体重）在基因型组中相似。有一种趋势，从他们的父亲继承TM-QTL羔羊脂肪少，肌肉略多于非载体。例如，通过活体动物CT扫描测量的TM/TM羔羊的胴体肌肉重量比+/+羔羊高2.8（P<0.05），胴体CT扫描测定的胴体肌重，TM/+组比+/+组高1.36% TM/+组羔羊的胴体脂肪重显著低于+/+组羔羊（-11.2%; P<0.05）。由于TM-QTL的两个主要效应（生长和肌肉）的作用模式明显不同，因此TM-QTL在绵羊产业中的最佳商业应用需要考虑。
TM-QTL is a quantitative trait locus (QTL) on ovine chromosome 18 (OAR18) known to affect loin muscling in Texel sheep. Previous work suggested that its mode of inheritance is consistent with paternal polar overdominance, but this has yet to be formally demonstrated. This study used purebred Texel sheep segregating for TM-QTL to confirm its presence in the chromosomal region in which it was first reported and to determine its pattern of inheritance. To do so, this study used the first available data from a Texel flock, which included homozygote TM-QTL carriers (TM/TM; n=34) in addition to homozygote non-carriers (+/+; n=40 and, heterozygote TM-QTL-carriers inheriting TM-QTL from their sire (TM/+; n=53) or their dam (+/TM; n=17). Phenotypes included a wide range of loin muscling, carcass composition and tissue distribution traits. The presence of a QTL affecting ultrasound muscle depth on OAR18 was confirmed with a paternal QTL effect ranging from +0.54 to +2.82 mm UMD (s.e. 0.37 to 0.57 mm) across the sires segregating for TM-QTL. Loin muscle width, depth and area, loin muscle volume and dissected M. longissimus lumborum weight were significantly greater for TM/+ than +/+ lambs (+2.9% to +7.9%; P<0.05). There was significant evidence that the effect of TM-QTL on the various loin muscling traits measured was paternally polar overdominant (P<0.05). In contrast, there was an additive effect of TM-QTL on both live weight at 20 weeks and carcass weight; TM/TM animals were significantly (P<0.05) heavier than +/+ (+11.1% and +7.3%, respectively) and +/TM animals (+11.9% and +11.7%, respectively), with TM/+ intermediate. Weights of the leg, saddle and shoulder region (corrected for carcass weight) were similar in the genotypic groups. There was a tendency for lambs inheriting TM-QTL from their sire to be less fat with slightly more muscle than non-carriers. For example, carcass muscle weight measured by live animal CT-scanning was 2.8% higher in TM/TM than +/+ lambs (P<0.05), carcass muscle weight measured by carcass CT-scanning was 1.36% higher in TM/+ than +/+ lambs (P<0.05), and weight of fat trimmed from the carcass cuts was significantly lower for TM/+ than +/+ lambs (-11.2%; P<0.05). No negative effects of TM-QTL on carcass traits were found. Optimal commercial use of TM-QTL within the sheep industry would require some consideration, due to the apparently different mode of action of the two main effects of TM-QTL (on growth and muscling).