The Chinese tree shrew (Tupaia belangeri chine­nsis), a closer affinity to primates, is increasingly considered as a viable alternative animal model for biomedical research due to a variety of unique characteristics, e.g., small adult body size, short reproductive cycle and life span, low cost of maintenance. While the recently published genome of the Chinese tree shrew greatly extends the necessary knowledge needed to make it an effective animal model, further study of the genome may facilitate new insights into the applicability of this model.

YAO Yonggang (Kunming Institute of Zoology, Chinese Academy of Sciences) and his research team used the available Chinese tree shrew genome information and compared the evolutionary pattern of 407 locomotion system related orthologs among five mammals (human, rhesus monkey, mouse, rat and dog) and the Chinese tree shrew. They identified 29 genes with significantly high ω (Ka/Ks ratio, a ratio greater than one implies positive or Darwinian selection) values and 48 amino acid sites in 14 genes showed significant evidence of positive selection in the Chinese tree shrew. Some of these positively selected genes, e.g. HOXA6 (homeobox A6) and AVP (arginine vasopressin), play important roles in muscle contraction or skeletal morphogenesis.

These results provide some important clues in understanding the genetic bases of locomotion ability and adaptation in Chinese tree shrew. The details could be found in Zoological Research (http://www.zoores.ac.cn/EN/abstract/abstract3483.shtml).

(By Long Nie)