Fellow scienceblogger Evolgen has seen the light—evo-devo is wonderful. He’s attending a meeting and listening to some of the bigwigs in the field talk about their work, in particular some research on the evolution of gene regulation. While noting that this is clearly important stuff, he also mentions some of the bickering going on about the relative importance of changes in cis regulatory elements (CREs) vs. trans acting elements, transcription factors. I’ve got a longer write-up of the subject, but if you don’t want to read all of that, the issue is about where the cool stuff in the evolution of morphology is going on. Transcription factors are gene products that bind to regulatory regions of other genes, and change their pattern of expression. The things they bind to are the CREs, which are non-coding regions of DNA associated with particular genes.