title: Evaluating the phylogenetic position of Chinese tree shrew (Tupaia belangeri chinensis) based on complete mitochondrial genome: implication for using tree shrew as an alternative experimental animal to primates in biomedical research.
abstract: Tree shrew (Tupaia belangeri) is currently placed in Order Scandentia and has a wide distribution in Southeast Asia and Southwest China. Due to its unique characteristics, such as small body size, high brain-to-body mass ratio, short reproductive cycle and life span, and low-cost of maintenance, tree shrew has been proposed to be an alternative experimental animal to primates in biomedical research. However, there are some debates regarding the exact phylogenetic affinity of tree shrew to primates. In this study, we determined the mtDNA entire genomes of three Chinese tree shrews (T. belangeri chinensis) and one Malayan flying lemur (Galeopterus variegatus). Combined with the published data for species in Euarchonta, we intended to discern the phylogenetic relationship among representative species of Dermoptera, Scandentia and Primates. The mtDNA genomes of Chinese tree shrews and Malayan flying lemur shared similar gene organization and structure with those of other mammals. Phylogenetic analysis based on 12 concatenated mitochondrial protein-encoding genes revealed a closer relationship between species of Scandentia and Glires, whereas species of Dermoptera were clustered with Primates. This pattern was consistent with previously reported phylogeny based on mtDNA data, but differed from the one reconstructed on the basis of nuclear genes. Our result suggested that the matrilineal affinity of tree shrew to primates may not be as close as we had thought. The ongoing project for sequencing the entire genome of Chinese tree shrew will provide more information to clarify this important issue.
authors.affiliation: Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan 650223, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
authors.forename: Shi-Yi
authors.initials: SY
authors.lastname: Chen
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Nie
authors.forename: Xue-Long
authors.initials: XL
authors.lastname: Jiang
authors.forename: Yong-Gang
authors.initials: YG
authors.lastname: Yao
mesh_terms: D023401:Animal Use Alternatives; D000818:Animals; D001483:Base Sequence; D001499:Bayes Theorem; D035843:Biomedical Research / Q000379:methods; D002681:China; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics*; D050259:Genes, Mitochondrial / Q000235:genetics; D054629:Genome, Mitochondrial / Q000235:genetics*; D008390:Markov Chains; D008969:Molecular Sequence Data; D009010:Monte Carlo Method; D010802:Phylogeny; D011323:Primates / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014417:Tupaia / Q000145:classification / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial