摘要
目的比较SARS冠状病毒(SARS-CoV)与第1至第3组(其他3组)冠状病毒的中性突变速率之异同,为更深入研究SARS-CoV起源提供新的思路。方法在美国国立生物技术信息中心中获取其他3组26条病毒序列,同时选取7条SARS-CoV序列。计算各病毒株5个主要基因串联序列的同义替换核苷酸的数量(Ks值),以此值与时间创建散点图,并进行直线拟合,取得各自中性突变速率并比较。结果 SARS-CoV中性突变速率为7.33×10-6/位点.天,而其他3组冠状病毒为2×10-6/位点.天,仅约前者的1/3.5,但决定系数R2极低,无意义。经多种拟合检验,发现标本量和离散性不是本文R2低值的主要原因。结论用同一方法对SARS-CoV和其他3组冠状病毒的中性突变速率进行比较研究,结果显示两者明显不同或具不同的模式;提示和其他3组冠状病毒相比较,SARS-CoV在分子进化或起源模式上似有特别之处。
Objective To compare the neutral mutation rate between the SARS-CoV and the other three groups（G1,G2 and G3） of Coronavirus,in order to provide new ideas for research deeply into the origin of SARS-CoV.Methods We obtained 26 sequences of G1,G2,G3 of Coronavirus and seven sequences of SARS-CoV from NCBI.The Pamilo-Bianchi-Li model was used to calculate the number of synonymous substitutions per synonymous site,Ks,for the concatenated five known major coding sequences of Coronavirus.A plot of Ks for the concatenated coding sequences vs.the sampling dates was established.The slope of the fitted line from the linear regression model gives the estimation of the neutral mutation rate.Results The neutral mutation rate of SARS-CoV was 7.33×10-6nt-1·day-1,the other three groups was 2.0×10-6nt-1·day-1,and the later was only 1/3.5 of the former,but the coefficient of determination（R2） is low extremely,and meaningless.Fitted by a variety of tests,we found the number of specimens and the dispersion were not the main reason for low R2 in this volume.Conclusions The comparative study on neutral mutation rate of SARS-CoV and the other three groups of coronaviruses using the same method shows there are significant differences or different modes between the two groups.It seems that there are some special aspects on the mode of molecular evolution or origin of SARS-CoV compared with the other three groups of coronavirus.
出处
《中华疾病控制杂志》
CAS
2011年第12期1026-1030,共5页
Chinese Journal of Disease Control & Prevention
基金
国家科技部卫生部保密课题(2004-2006年度)
全军医药卫生科研基金(03F020-1)
