莱芜猪高肌内脂肪沉积特性的遗传机理

At present, (Intramuscular, Fat) IMF content has become an important indicator of the quality of pork, and has a significant positive effect on the meat tenderness, juiciness and flavor. It was difficult to measure the content of IMF in vivo and early stage. How to guarantee the lean meat rate, increase the content of IMF, but also become a new target of breeders. Animal fat deposition is a complex process with participation of many genes. Therefore, the molecular regulation mechanism to fully reveal the fat deposition, cannot only limit to the research on a small number of genes, but as far as possible separation of differentially expressed genes. Laiwu and Large Yorkshire pigs as the reseach animal, they have significant difference on the meat quality charaxteristics. The high-throughput sequencing technology (NGS) will be using comprehensively analysis on porcine muscle transcriptome gene, and screening the intramuscular fat content (Intramuscular Fat, IMF) difference related geng by sequence. In order to reveal the genetic mechanism of Laiwu pig High IMF deposition, provides reference for molecular breeding excellent pigs; at the same time, provide the basis for the study of different metabolic mechanism of intramuscular fat and backfat thickness further. In addition, the pig as animal model to study the best mechanism of obesity, but also opened up a new way for human obesity.

目前，在对猪肉质的评定指标中，（Intramuscular Fat, IMF）IMF的含量已成为猪肉品质的一个重要的指标，它对肉的嫩度、多汁性和风味有明显的正效应。由于IMF含量在活体和早期难测量，常规育种较难进行。如何在保证瘦肉率的前提下，提高IMF含量，也成为育种工作者的新目标。动物脂肪沉积是由众多基因共同参与的复杂过程。因此，要全面揭示脂肪沉积的分子调控机制，不能仅局限于对一小部分基因的研究，而应尽可能多地分离出差异表达基因，并进行研究。本研究以莱芜猪和大白猪为研究对象，采用高通量测序技术（NGS）对猪肌肉组织转录组基因进行全面系统的分析，筛选与肌内脂肪含量相关的差异表达基因序列。以揭示莱芜猪高IMF沉积遗传机理，为优良肉猪的分子育种提供了参考；同时为进一步研究肌内脂肪与背膘厚的不同代谢机理提供基础。另外，猪作为研究肥胖机理的最佳模式动物，也为人类肥胖疾病的研究开辟了新的思路。

采用新一代高通量测序技术Illumina’s Solexa平台对的莱芜猪和大白猪肌肉组织的转录组进行测序，全面系统的分析猪基因组序列。通过对测序结果里面含有带接头的、低质量的rawreads进行了过滤，得到了经过清理的约90G的莱芜猪和大白猪脂肪沉积差异表达基因片段数据。并对mRNA的基因覆盖类型和可变剪切进行了分析。对mRNA的表达富集最显著的30个代谢通路进行了KEGG分析，发现其中参与氧化磷酸化的mRNA在两个不同样本里的丰度都最高，负责调控心脏肌肉收缩的mRNA丰度也处于很高的水平。GO相关的图表可以看出大白猪和莱芜猪的mRNA不同代谢通路丰度不同。可以看出大白猪的参与水解酶负调控、内肽酶负调控、多肽活性负调控的mRNA丰度较莱芜猪较高。而莱芜猪里参与氧化还原和细胞器调控的mRNA种类丰度较大白猪高。这些给我们分析脂肪代谢提供了很多启示。本研究也对长链lncRNA进行了筛选，每条lncRNA的外显子个数集中在2-4个，lncRNA的开放阅读框长度集中在40-120个。研究对测序结果进行qRT-PCR验证分析，为构建肌肉高低脂肪沉积差异库提供准确的候选基因信息；挑选到PID1这个基因进行进一步的研究，通过构建真核表达载体在细胞水平上验证，结合验证结果通过构建转基因表达载体在动物水平进行验证。