Oct. 24-26, 2009, Yingjie Overseas Exchange Center, Peking University, Beijing, China中文版

Giant Panda Genomic Data Provide Insight into the Birth-and-Death Process of Mammalian Major Histocompatibility Complex Class II Genes

Shengguo Fang

Zhejiang University, 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.

Shengguo Fang

Zhejiang University, China

Biography

Sheng-Guo Fang is the Professor of Life Sciences at Zhejiang University, Director of State Conservation Center for Gene Resources of Endangered Wildlife, Director of the Key Laboratory of Conservation Genetics and Reproductive Biology for Endangered Wild Animals of the Ministry of Education, P. R. China. He obtained his B.S. in Zoology at Sichuan University in 1984 and was a Research Intern of Avian Taxonomy and Ecology at Tibet Plateau Institute of Biology from 1984 to 1987. In 1987, He came back to Sichuan and set up Molecular Biology Institute at Sichuan Normal University. From 1987 to 1998, he served as the Execute Director of Molecular Biology Institute and became a Research Associate of Conservation Genetics and Molecular Ecology for Endangered Animals at Sichuan Normal University in 1994. In 1998, he moved to Zhejiang University and set up two organizations there: the Key Laboratory of Conservation Genetics and Reproductive Biology for Endangered Wild Animals of the Ministry of Education (in 2000) and State Conservation Center for Gene Resources of Endangered Wildlife (in 2001). He has been a Professor of Life Sciences at Zhejiang University since 1999 and has served as the directors of these two organizations since 2000 and 2001, respectively. 

Professor Fang’s research areas include the development of non-invasive molecular approaches in animal ecology, the preparation of DNA makers, and the use of molecular tools to analyze genetic diversity, population structure and behavior ecology of rare or cryptic species. His research interests are mainly focused on the ecology and conservation of giant pandas, Chinese alligators, crested ibises and etc. Since 1987, he has engaged in the conservation of giant pandas. He developed a novel method to extract high molecular weight DNA from formalin-fixed specimens and prepared a novel gp2000 probe specific to giant pandas, based on which he revealed significant genetic differentiation of Qinling individuals from other giant pandas. Subsequently, combined with morphological evidence, he characterized a new giant panda subspecies, Ailuropoda melanoleuca qinlingensis. Because of these achievements for the giant panda, he won the Second Class National Invention Prize (1999) and obtained a grant from National Science Fund for Distinguished Young Scholars (2003-2007). At present, his studies on the conservation of giant pandas are carried out at the genome level, especially at the MHC partial genome scale.

Professor Fang currently serves as the chief scientists of Zhejiang Chinese Alligator Reintroduction Project and Zhejiang Crested Ibis Reintroduction Project. In addition, he was elected as vice president of Chinese Mammal Society, a member of Giant Panda Specialist Group, a member of IUCN Crocodile Specialist Group.