I have gene lists that I want to compare based on how well they were conserved across human and mice. Is there an established way of doing this? My first impulse was to compare identity directly but since genes have differing lengths and differing functional sizes of differing importance, a measure just based on sequence identity seems like a bad way of comparing any two genes to each other.
If you are interested in sequence conservation across species then you should look into 1) PhastCons scores (http://genome.ucsc.edu/goldenPath/help/phastCons.html, http://genome.cshlp.org/content/15/8/1034.long) or 2) GERP++ scores (http://mendel.stanford.edu/SidowLab/downloads/gerp/)