Zhou Quan-Yong, Huang Jiang-Nan, Xiong Yuan-Zhu, Zhao Shu-Hong
Key Laboratory of Agricultural Animal Genetics, Breeding, and Reproduction of Ministry of Education & Key Laboratory of Swine Genetics and Breeding of Ministry of Agriculture, Huazhong Agricultural University, Wuhan, PR China.
Genes Genet Syst. 2007 Jun;82(3):265-9. doi: 10.1266/ggs.82.265.
Imprinted genes are expressed monoallelically depending on their parental origin, and escape the Mendel's laws of heredity. They play important roles in the mammalian development, growth, and behavior. Placenta is a key tissue for the normal development and growth of fetus. It is also used to illuminate the evolution of genomic imprinting. In this study, we cloned the porcine GATM and PEG10 genes. Somatic cell hybrid panel (SCHP) and porcine radiation hybrid (IMpRH) panel were employed to locate GATM and PEG10 genes to SSC1q12-21 and SSC9p13-21, respectively. By sequencing PCR products, we detected several cSNPs in the two genes. The BseLI (GATM) and TaqI (PEG10) polymorphisms were used to investigate the allele frequencies in different pig breeds and the imprinting status in porcine placentas on days 75 and 90 of gestation. The results showed that for the GATM BseLI polymorphism, the Yorkshire and Duroc pigs had higher allele frequencies at the G allele, whereas the local pigs had higher allele frequencies at the A allele. Expression and sequencing analyses showed that both alleles were expressed for the GATM gene, indicating the GATM was not imprinted in the porcine placentas on days 75 and 90 of gestation. The allele frequencies of TaqI polymorphism for PEG10 gene were significantly different in native Chinese Erhualian breed comparing to Yorkshire. PEG10 was monoallelically expressed, showing the PEG10 gene may be imprinted in porcine placentas on days 75 and 90 of gestation.
印记基因根据其亲本来源单等位基因表达，并且不受孟德尔遗传定律的约束。它们在哺乳动物的发育、生长和行为中发挥着重要作用。胎盘是胎儿正常发育和生长的关键组织。它也被用于阐明基因组印记的进化。在本研究中，我们克隆了猪的GATM和PEG10基因。利用体细胞杂种板（SCHP）和猪辐射杂种（IMpRH）板分别将GATM和PEG10基因定位到猪1号染色体q12 - 21和猪9号染色体p13 - 21。通过对PCR产物进行测序，我们在这两个基因中检测到了几个cSNP。利用BseLI（GATM）和TaqI（PEG10）多态性来研究不同猪品种中的等位基因频率以及妊娠75天和90天时猪胎盘的印记状态。结果表明，对于GATM BseLI多态性，约克夏猪和杜洛克猪在G等位基因上具有较高的等位基因频率，而本地猪在A等位基因上具有较高的等位基因频率。表达和测序分析表明，GATM基因的两个等位基因均有表达，这表明在妊娠75天和90天时GATM基因在猪胎盘中没有印记。与约克夏猪相比，中国本土二花脸猪中PEG10基因TaqI多态性的等位基因频率存在显著差异。PEG10基因单等位基因表达，这表明PEG10基因在妊娠75天和90天时的猪胎盘中可能是印记的。
