Polymorphism of coupled indels in porcine TNNC2 alters its transcript splicing and is associated with meat quality traits
Polymorphism of coupled indels in porcine TNNC2 alters its transcript splicing and is associated with meat quality traits
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猪 TNNC2 中耦合插入缺失的多态性改变其转录本剪接并与肉品质性状相关
DOI：
10.1111/age.13167
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发表时间：
2022-01-05
期刊：
影响因子：
2.4
通讯作者：
Xu，Xuewen
中科院分区：
文献类型：
--
作者：
Ma，Tingting;Liu，Yan;Xu，Xuewen
TNNC2基因编码肌钙蛋白复合物的快速骨骼C亚基，该亚基在横纹肌收缩的调节中起着至关重要的作用，并且可能是猪肉品质的候选基因。在这里，我们在猪TNNC2中鉴定出了耦合插入/缺失（indel）变体，即17 bp插入和11 bp缺失。耦合的插入缺失变体提供了替代剪接供体位点，并导致 TNNC2-201 的第一个外显子发生 42 bp 截短，从而导致 TNNC2-201 的表达增加。两种 indel 变体的多态性与平均背膘厚度 (p= 3.16 × 10−3)、屠宰后 24 小时 pH 值 (p= 4.31 × 10−4)、肌内脂肪 (IMF) 含量 (p= 1.54 × 10−2) 和肌纤维横截面积 (p= 2.86 × 10−2) 相关背长肌在人群中 425 杜洛克（♂）×陆川（♀）猪。在 1,304 头商业杂交猪的独立群体中，我们进一步证实它与背长肌的 IMF 含量 (p= 1.75 × 10−4)、屠宰后 45 分钟 pH 值 (p= 6.34 × 10−3) 和滴水损失 (p= 2.88 × 10−2) 相关。突变等位基因频率的增加与 IMF 含量增加、肌纤维变小和相对适中的 pH 值有关。此外，我们在陆川猪和桐城猪中检测到突变等位基因频率为96.67%，在桐城猪中为86.67%，而在杜洛克猪中为0.91%，在长白猪中为2.04%，在约克夏猪和皮特兰猪中为0%，这表明其在瘦肉型猪品种和中国地方猪品种中的分布相反。目前的结果确立了 TNNC2 的耦合插入缺失变体作为肉质改良的新型分子标记。
TheTNNC2gene encodes the fast‐skeletal C subunit of the troponin complex that plays a vital role in the regulation of striated muscle contraction and could be a candidate gene for pork quality. Here, we identified coupled insertion/deletion (indel) variants, a 17‐bp insertion and an 11‐bp deletion, in porcineTNNC2. The coupled indel variants provide an alternative splicing donor site and cause a 42‐bp truncation in the first exon ofTNNC2‐201, leading to increased expression ofTNNC2‐201. Polymorphism of the two indel variants is associated with the average backfat thickness (p= 3.16 × 10−3), pH value 24 h post‐slaughter (p= 4.31 × 10−4), intramuscular fat (IMF) content (p= 1.54 × 10−2), and myofiber cross‐sectional area (p= 2.86 × 10−2) oflongissimus dorsiin a population of 425 Duroc (♂) × Luchuan (♀) pigs. In an independent population of 1,304 commercial hybrid pigs, we further confirmed that it is associated with the IMF content (p= 1.75 × 10−4), pH value 45 min post‐slaughter (p= 6.34 × 10−3), and drip loss (p= 2.88 × 10−2) of thelongissimus dorsimuscle. An increased frequency of the mutant allele is linked to increased IMF content, smaller myofibers, and a relatively moderate pH value. Furthermore, we detected a mutant allele frequency of 96.67% in Luchuan pigs and 86.67% in Tongcheng pigs, whereas the frequency was 0.91% in Duroc pigs, 2.04% in Landrace pigs, and 0% in Yorkshire and Pietrain pigs, indicating its opposing distributions in lean‐type and Chinese local pig breeds. The present results establish coupled indel variants ofTNNC2as a novel molecular marker for meat quality improvement.