(Please forgive me if this is a trivial/stupid question.)
Say a genome has n genes that code for proteins. Sampling the mRNA pool produced by this genome at time t yields m distinct mRNAs.
My question is, are there any estimates for what m/n is in general. (Like 5%, 50%, etc.) That is, what fraction of the genome (that codes for genes) is expressed at any give arbitrary time point?
If I were to pose this question a bit differently: say I have RNA-seq reads for an organism with a fully sequenced genome. What is the "typical" (?) mapping rate I should expect if I were to have the reads mapped to the genome (or to its CDS subset)?