Institute of Animal Science, University of Bonn, Endenicher Allee 15, Bonn, Germany.
BMC Genet. 2011 Jul 13;12:62. doi: 10.1186/1471-2156-12-62.
Serum lipids are associated with many serious cardiovascular diseases and obesity problems. Many quantitative trait loci (QTL) have been reported in the pig mostly for performance traits but very few for the serum lipid traits. In contrast, remarkable numbers of QTL are mapped for serum lipids in humans and mice. Therefore, the objective of this research was to investigate the chromosomal regions influencing the serum level of the total cholesterol (CT), triglyceride (TG), high density protein cholesterol (HDL) and low density protein cholesterol (LDL) in pigs. For this purpose, a total of 330 animals from a Duroc × Pietrain F2 resource population were phenotyped for serum lipids using ELISA and were genotyped by using 122 microsatellite markers covering all porcine autosomes for QTL study in QTL Express. Blood sampling was performed at approximately 175 days before slaughter of the pig.
Most of the traits were correlated with each other and were influenced by average daily gain, slaughter date and age. A total of 18 QTL including three QTL with imprinting effect were identified on 11 different porcine autosomes. Most of the QTL reached to 5% chromosome-wide (CW) level significance including a QTL at 5% experiment-wide (GW) and a QTL at 1% GW level significance. Of these QTL four were identified for both the CT and LDL and two QTL were identified for both the TG and LDL. Moreover, three chromosomal regions were detected for the HDL/LDL ratio in this study. One QTL for HDL on SSC2 and two QTL for TG on SSC11 and 17 were detected with imprinting effect. The highly significant QTL (1% GW) was detected for LDL at 82 cM on SSC1, whereas significant QTL (5% GW) was identified for HDL/LDL on SSC1 at 87 cM. Chromosomal regions with pleiotropic effects were detected for correlated traits on SSC1, 7 and 12. Most of the QTL identified for serum lipid traits correspond with the previously reported QTL for similar traits in other mammals. Two novel QTL on SSC16 for HDL and HDL/LDL ratio and an imprinted QTL on SSS17 for TG were detected in the pig for the first time.
The newly identified QTL are potentially involved in lipid metabolism. The results of this work shed new light on the genetic background of serum lipid concentrations and these findings will be helpful to identify candidate genes in these QTL regions related to lipid metabolism and serum lipid concentrations in pigs.
血清脂质与许多严重的心血管疾病和肥胖问题有关。猪的大多数性能特征都有许多数量性状基因座（QTL）被报道，但很少有与血清脂质特征相关的 QTL。相比之下，人类和小鼠的血清脂质 QTL 数量非常多。因此，本研究的目的是研究影响猪血清总胆固醇（CT）、甘油三酯（TG）、高密度蛋白胆固醇（HDL）和低密度蛋白胆固醇（LDL）水平的染色体区域。为此，使用 ELISA 对来自杜洛克×皮特兰 F2 资源群体的 330 头动物进行了血清脂质表型分析，并使用覆盖所有猪染色体的 122 个微卫星标记对 QTL 进行了基因型分析，用于在 QTL Express 中进行 QTL 研究。血液取样是在猪屠宰前约 175 天进行的。
大多数性状相互关联，并受到平均日增重、屠宰日期和年龄的影响。在 11 条不同的猪染色体上共鉴定到 18 个 QTL，包括 3 个具有印记效应的 QTL。大多数 QTL 达到 5%实验范围（GW）水平的显著意义，包括一个在 5%实验范围（GW）和一个在 1% GW 水平显著的 QTL。在这些 QTL 中，有 4 个被鉴定为 CT 和 LDL，有 2 个被鉴定为 TG 和 LDL。此外，在本研究中还检测到了 HDL/LDL 比值的三个染色体区域。在 SSC2 上检测到一个 HDL 的 QTL，在 SSC11 和 17 上检测到两个 TG 的 QTL 具有印记效应。在 SSC1 上 LDL 处检测到一个高度显著的 QTL（1%GW），在 SSC1 上 87cm 处检测到一个 HDL/LDL 的显著 QTL（5%GW）。在 SSC1、7 和 12 上检测到与相关性状具有多效性效应的染色体区域。在其他哺乳动物中，与类似性状相关的血清脂质特征的大多数 QTL 与之前报道的 QTL 相对应。在猪中，首次在 SSC16 上检测到一个新的 HDL 和 HDL/LDL 比值的 QTL，在 SSS17 上检测到一个 TG 的印记 QTL。
新鉴定的 QTL 可能参与脂质代谢。这项工作的结果为血清脂质浓度的遗传背景提供了新的见解，这些发现将有助于识别与脂质代谢和猪血清脂质浓度相关的这些 QTL 区域的候选基因。
