The acquisition of Orca Biosciences Inc. by Epigenomics AG, to be announced today, consolidates the only two companies focusing on DNA methylation patterns. While DNA methylation and the factors that affect it are less well studied than genetic polymorphisms, DNA methylation may yet become equally important in understanding disease. In contrast to the relatively static picture that SNP analysis may provide, DNA methylation patterns change over time, and thus may have utility in indicating disease status.

One way that cells regulate gene expression over the long term is by methylation of the DNA base cytosine, which switches off expression of the gene. The methyl groups prevent transcription factors that produce mRNA from binding to the DNA. Methylation normally controls which copy