On Human Genes and Silent Mutations

Both Carl Zimmer and Larry Moran have posts on the gene content in the human genome. Carl points out that the estimate of the total number of genes in the human genome is decreasing, but we still don’t know what a whole bunch of those genes do (according to the one database he searched). Larry’s post deals with what he considers a misconception regarding the historical estimates of gene content in humans. He argues that, while the estimates of the number of protein coding genes have decreased over the years, they haven’t really decreased as much as some people seem to think (from about 40,000 to about 20,000); the idea that humans have more than 100,000 genes was never all that common.

Both of those posts are good reads if you’re interested in gene content — and by gene, I mean unique protein coding sequences. But what about mutations in genes? Seed is running an article on research into synonymous mutations with deleterious phenotypes in humans. The piece is rife with all the eureka-esque “look what we know now” and “it’s a paradigm shift” coverage you expect in science news — we’ve known for quite a while that synonymous mutations are not always neutral (see here for some more info), and we’re only now beginning to understand their role in human disease — but it provides a decent introduction to this area of research. I do have a gripe with how the author confuses the neutral theory with the idea that synonymous mutations are truly “silent” changes, but this muddling of concepts doesn’t get in the way of the important points.