In previous essays (here and here), we learned that genes encoding new proteins can and do, often, arise de novo in the course of evolution, contradicting one of the central tenets of ID proponents. The means by which these genes arise are many. One of these, suggested by Cai at al. (the subject of one of the earlier essays), involved the adaptation of a gene encoding an evolutionarily-conserved non-coding RNA via the appearance, by mutation, of appropriate translation initiation and termination (“start” and “stop”) codons. This mechanism represents an intersection of sorts between the subject of protein evolution and another matter of discussion on these blogs, namely the existence, evolution, and “function” of junk DNA. In this essay, I review a 2007 study by Debrah Thompson and Roy Parker (“Cytoplasmic decay of intergenic transcripts in Saccharomyces cerevisiae”, Mol. Cell. Biol. 27, 92-101) that adds a great deal of clarity to this mode of gene and protein evolution.
Posted by Arthur Hunt 