Ouroboros' Kristen Fortney says two recent studies, one in BMC Bioinformatics and one in PLoS Genetics, show that aging changes the expression relationships between genes. Both studies also propose new methods for identifying genes that behave this way, she says, and the study in PLoS Genetics also makes a good case for the theory that the relationships between some related genes change as the genes age. "Crucially, the correlation between a pair of genes may change with age even when the average expression levels of both genes do not – so these new coexpression methods are complementary to traditional differential expression analyses of microarray data," Fortney writes.The team writing in BMC Bioinformatics developed a new way of identifying pairs of genes "differentially coexpressed with age," Fortney says, based on Haar wavelets designed to handle multiple ordered groups. And the team writing in PloS Genetics, she reports, showed that "coexpression patterns of groups of related genes become less coherent as animals age." Fortney adds that more analysis is needed to determine which of these differences in gene relationships "result from noise" and which ones are telling a new story.