国家濒危野生动植物种质基因保护中心主任、濒危野生动物保护遗传与繁殖教育部重点实验室主任、浙江大学生命科学院教授方盛国的研究小组1月7日在PloS One发表大熊猫基因组的最新研究成果。
研究人员深入的研究了大熊猫MHC基因的进化情况。通过对MHCⅡ型基因区域进行分析，结果显示，大熊猫基因组MHCⅡ基因序列中包含有26个转座子（其中17个有表达蛋白的活性），其中有10个为经典的MHCⅡ型基因（1DRA，2DRB，2DQA，3DQB，1DYB，1DPA和2DPB），4个非经典的MHCⅡ型基因（1DOA，1DOB，1DMA和1DMB）。其中，DYB与其他宿主相比较（小鼠、人、狗、牛）具有特异性，DYB是反刍动物特有的一个基因。研究小组绘制了基因进化树，对大熊猫的MHCⅡ型基因进行遗传学分析。（生物谷Bioon.com）
生物谷推荐原始出处：
PLoS ONE 4(1): e4147. doi:10.1371/journal.pone.0004147
Giant Panda Genomic Data Provide Insight into the Birth-and-Death Process of Mammalian Major Histocompatibility Complex Class II Genes
Qiu-Hong Wan1,2, Chang-Jun Zeng1,2, Xiao-Wei Ni1,2, Hui-Juan Pan1,2, Sheng-Guo Fang1,2*
1 College of Life Sciences, Zhejiang University, Hangzhou, People's Republic of China, 2 State Conservation Center for Gene Resources of Endangered Wildlife and the Key Laboratory of Conservation Genetics and Reproductive Biology for Endangered Wild Animals of the Ministry of Education, Hangzhou, People's Republic of China
Abstract
To gain an understanding of the genomic structure and evolutionary history of the giant panda major histocompatibility complex (MHC) genes, we determined a 636,503-bp nucleotide sequence spanning the MHC class II region. Analysis revealed that the MHC class II region from this rare species contained 26 loci (17 predicted to be expressed), of which 10 are classical class II genes (1 DRA, 2 DRB, 2 DQA, 3 DQB, 1 DYB, 1 DPA, and 2 DPB) and 4 are non-classical class II genes (1 DOA, 1 DOB, 1 DMA, and 1 DMB). The presence of DYB, a gene specific to ruminants, prompted a comparison of the giant panda class II sequence with those of humans, cats, dogs, cattle, pigs, and mice. The results indicated that birth and death events within the DQ and DRB-DY regions led to major lineage differences, with absence of these regions in the cat and in humans and mice respectively. The phylogenetic trees constructed using all expressed alpha and beta genes from marsupials and placental mammals showed that: (1) because marsupials carry loci corresponding to DR, DP, DO and DM genes, those subregions most likely developed before the divergence of marsupials and placental mammals, approximately 150 million years ago (MYA); (2) conversely, the DQ and DY regions must have evolved later, but before the radiation of placental mammals (100 MYA). As a result, the typical genomic structure of MHC class II genes for the giant panda is similar to that of the other placental mammals and corresponds to BTNL2~DR1~DQ~DR2~DY~DO_box~DP~COL11A2. Over the past 100 million years, there has been birth and death of mammalian DR, DQ, DY, and DP genes, an evolutionary process that has brought about the current species-specific genomic structure of the MHC class II region. Furthermore, facing certain similar pathogens, mammals have adopted intra-subregion (DR and DQ) and inter-subregion (between DQ and DP) convergent evolutionary strategies for their alpha and beta genes, respectively.
