| As it is easy to domesticate and breed and possesses physiological characteristics close to humans, Tibetan macaque could be ideal experimental animals in the study of various fields. In addition, with the organizational structure, and the physiological and metabolic functions of Tibetan macaque being similar to humans, they are likely to help us to understand similar human diseases and elucidate their pathogenesis. So as an ideal experimental animals, Tibetan macaque made an irreplaceable role compared with other laboratory animals. Sichuan snub-nosed monkey is one of the most beautiful primates, it has a high ornamental value. Because of the special phylogenetically site of snub-nosed monkey (between the Old World monkey and ape), the study of snub-nosed is important for us to recognize the evolutionary history of our human beings and thus has a high value of academic research.TLR is an immune-related gene family. It can recognizes distinct pathogen-associated molecular patterns (PAMPs) and can activate innate immunity and adaptive immunity after a series signal transduction pathways. So it plays an important role in the prevention and treatment of immune-related diseases. Through study of the selection pressure of TLR gene family in the evolution of Tibetan macaque and Sichuan snub-nosed monkey can be able to provide a theoretical foundation for the protection of the two national animals.In this study, the Sichuan Tibetan macaque and Sichuan snub-nosed monkey as the research object:1) The first time obtained the whole coding regions of TLR gene in the two species by PCR amplification and cloning techniques. The result display a similar structure as previous reported. The structures prediction by on line software possessed a typical structure, which is consists of extracellular, transmembrane and intracellular regions. The extracellular region is a leucine-rich repeat (LRR) region, LRR regions are related to recognition of a broad range of pathogen-associated molecular patterns (PAMP) from pathogens. There is a highly conserved Toll-interleukin1receptor (TIR) in intracellular region, it can interaction with TIR domain in adapter protein MyD88and responsible for signal transduction down stream.2) Homology analysis showed that either Tibetan macaque or Sichuan snub-nosed monkey has a high degree of homology with rhesus macaque (>97%). In comparison with other species also have a highly homology (70%-98%), indicating that the TLR is a conservative gene.3) The phylogenetic tree shows that in the species respect,3species belongs to Macaca clustered into a clade and then formed a big branch with Sichuan snub-nosed monkey, all the apes formed a clade with humans, and marmoset, as the New World monkey, clustered into a single clade. In the gene respect, the entire TLR gene family is divided into6branches. TLR1,TLR6and TLR10formed a clade; TLR2, TLR3, TLR4and TLR5clustered into a single clade separately; TLR1, TZR8and TLR9clustered into a clade.4) PAMAL was used to derivated the Macaca ancestor sequence and Old World monkey ancestor. When caculated the value of dN/dS between ancestor and species,we found that TLRA and TLR9in rhesus, TLR5in crab-eating macaque and TLR8in Tibetan macaque were under a strong positive selection, but when used one-tail Z test, each selection were not significantly. Divid the entire encoding region of TLR gene into TIR domain and non-TIR domain, the ω value was higher in non-TIR domain than in TIR domain,which sugessted that non-TIR domain was under a lower purifying selection pressure compared to TIR domain. From our date, TLR1, TLR3, TLR4, TLR6and TLR7in Macaca was evoluted more faster than Sichuan snub-nosed monkey. |
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