树鼩进化分类地位的分子证据

Molecular evidence on the phylogenetic position of tree shrews

树鼩隶属攀鼩目,广泛分布于东南亚、南亚和中国南部等地区。由于其独特的特点,如体型小、脑-体重比例高、生殖周期短、寿命短和饲养成本低等,在生物医学研究中被认为是可望替代灵长类动物的新型实验动物。然而,关于树鼩与灵长类动物的亲缘关系一直存在争议。明确树鼩的分类地位是创建实验动物的重要研究基础。该文介绍了近年来关于树鼩分类地位探讨的分子证据。在现有的研究中,大部分核DNA序列研究,包括近期树鼩全基因组序列分析,都支持树鼩是灵长动物的近缘旁系群,然而绝大部分基于线粒体DNA序列的研究却显示树鼩与啮齿动物的亲缘关系更为接近。这样的分歧主要是由于线粒体序列和核基因数据的差异以及不同的算法导致。综合现有不同DNA数据的研究结果,作者认为树鼩作为灵长类的近亲这一结论应该成为共识。

The tree shrew is currently located in the Order Scandentia and is widely distributed in Southeast Asia, South Asia, and South 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, the tree shrew has been proposed as an alternative experimental animal to primates in biomedical research. However, there is unresolved debate regarding the phylogenetic affinity of tree shrews to primates and their phylogenetic position in Euarchontoglires. To help settle this debate, we summarized the available molecular evidence on the phylogenetic position of the tree shrew. Most nuclear DNA data, including recent genome data, suggested that the tree shrew belongs to the Euarchonta clade harboring primates and flying lemurs （colugos）. However, analyses of mitochondrial DNA （mtDNA） data suggested a close relationship to lagomorphs and rodents. These different clustering patterns could be explained by nuclear gene data and mtDNA data discrepancies, as well as the different phylogenetic approaches used in previous studies. Taking all available conclusions together, the robust data from whole genome of this species supports tree shrews being genetically closely related to primates.