This March 2005 data freeze provides estimates of mRNA expression in adult cerebellum of 48 lines of mice including 45 BXD recombinant inbred strains, C57BL/6J, DBA/2J, and F1 hybrids. Data were generated by a consortium of investigators at St. Jude Children's Research Hospital (SJ) and the University of Tennessee Health Science Center (UT). Cerebellar samples were hybridized in small pools (n = 3) to Affymetrix M430A and B arrays. This particular data set was processed using the Microarray Suite 5 (<a data-cke-saved-href="http://www.affymetrix.com/support/technical/whitepapers/sadd_whitepaper.pdf" href="http://www.affymetrix.com/support/technical/whitepapers/sadd_whitepaper.pdf" _blank"="" class="fs14">MAS 5) protocol. To simplify comparisons among transforms, MAS5 values of each array were adjusted to an average of 8 units and a standard deviation of 2 units.