Contrasting patterns of expression divergence in early and late stages of population divergence in mice

We compared gene expression differences in the polytypic species complex Mus musculus (Mus musculus musculus, Mus musculus domesticus, Mus musculus castaneus and Mus musculus ssp) with that of Mus spretus via oligonucleotide microarrays representing more than 20,000 genes. Analysis of the results by two way ANOVA statistics suggests that the most genes with significant differences in expression levels among the subspecies are found in liver and kidney and the least in testis. This picture is different when one compares with Mus spretus, where the largest number of differences is found in testis. Keywords: multi-species comparison The design we employed is a reference design. All tissues were hybridized against a pool of that same tissue from 9 C57BL6 mice. All mice were roughly 12 weeks of age. To control for biological variation, we have used several individual males from each sub-species. RNA was isolated from three different organs, namely brain, liver/kidney and testis.