1. Regulating Evolution: How Gene Switches Make Life

Comment #177454 by magic_bullets on May 9, 2008 at 5:54 am

As I'm a molecular geneticist I'll try to say something about the definition of the word gene: I think it's just out of convenience that molecular biologist define gene as more or less the "open reading frame" (=ORF), i.e. the region between the start and the stop codons. This is because when you're studying a particular DNA sequence, the gene part (=ORF) is the easy part to spot (because it is defined by the start and the stop codons). All other parts that might "belong" to a gene, such as promoters, enhancers etc. is much more difficult to figure out. It therefore makes sense to define them separately.

To Partisan: Our DNA is of course not identical to the DNA of our amphibian ancestors, but we do have genes of which the counterpart can be found in our amphibian ancestors as well as in fruit flies and even fungi and bacteria. For example the Hox genes, which was mentioned by Geoff, was first discovered in the fruit fly. Imagine the suprise when scientists later found those same genes in humans!

For anybody who would like a nice introduction to evo devo I recommend the book "Endless forms most beautiful" by Sean B. Carroll (one of the authors of this article).