Now I am studying the relationship between gene expression and genome features ,such as intron length.So I need some expression data of model organism.I have download tair's data ,but its readme file said that the expression data are value are red/green ratio,are they the ratio of control/test expression level.dose it can be used as gene's expression level.If not,which data I can use for my research.

You might look at real time PCR. That sort of data often shows relative changes in gene expression, but I think you can also quantify expression absolutely, though you might need to use a special control for this.

wanghf said:

Now I am studying the relationship between gene expression and genome features ,such as intron length.So I need some expression data of model organism.I have download tair's data ,but its readme file said that the expression data are value are red/green ratio,are they the ratio of control/test expression level.dose it can be used as gene's expression level.If not,which data I can use for my research.

The two-color microarray data is usually not the direct expression result for any gene, because it is comparing the experimental group with the control group.
You may look at the Affymetrix microarray data, since one data set is one for gene expression. But it is still variable depending on the source of the data.

Id start by picking the organism. C. elegans or drosophila are probably your best bets. For C. elegans start at wormbase, there's an amazing amount of info there.

http://www.wormbase.org/

Good luck hunting

RB

It depends what you are trying to accomplish with your study, you might have better luck at one of the mroe general purpose data repositories like NCBI's gene expression omnibus (GEO). See an earlier post in the bioinformatics group here.

R Bishop said:

Id start by picking the organism. C. elegans or drosophila are probably your best bets. For C. elegans start at wormbase, there's an amazing amount of info there. http://www.wormbase.org/ Good luck hunting RB