國家瀕危野生動植物種質基因保護中心主任,、瀕危野生動物保護遺傳與繁殖教育部重點實驗室主任,、浙江大學生命科學院教授方盛國的研究小組1月7日在PloS One發(fā)表大熊貓基因組的最新研究成果。
研究人員深入的研究了大熊貓MHC基因的進化情況,。通過對MHCⅡ型基因區(qū)域進行分析,，結果顯示，大熊貓基因組MHCⅡ基因序列中包含有26個轉座子（其中17個有表達蛋白的活性）,，其中有10個為經典的MHCⅡ型基因（1DRA，2DRB,，2DQA,，3DQB，1DYB,，1DPA和2DPB）,，4個非經典的MHCⅡ型基因（1DOA，1DOB,，1DMA和1DMB）,。其中,，DYB與其他宿主相比較（小鼠、人,、狗,、牛）具有特異性，DYB是反芻動物特有的一個基因,。研究小組繪制了基因進化樹,，對大熊貓的MHCⅡ型基因進行遺傳學分析。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
