发信人: springerz (乡愁四韵), 信区: Biology
标 题: Re: 请教: A question in Molecular Evolution
发信站: The unknown SPACE (Fri Dec 13 14:42:37 2002), 站内信件


positive selection,u will expect to seea high ratio of non-synonymous
substitution to sys.
purifying selection gives u a low value of above ratio
increased rate theoretically affect sys. and non-sys. equally,this is
theoretical,but actually there is biased substitution
【 在 brights (忍冬) 的大作中提到: 】
: An increased rate of substitutions in the sequence of a protein coding segment
: of DNA for a given clade of organisms could be due to positive selection
: acting upon the protein product, relaxed purifying selection or an increased
: mutation rate. How could you distinguish between these three alternatives ?
: Are there any other alternatives I failed to mention? What are they?
: thanks a lot le....


--
※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 144.92.]