We’re all mutants?
From the Herald (actually from the Independent)
The rise in the number of overweight children in Western countries may be as much to do with their genes as their diet and exercise levels,
In fact, just about the only completely uncontroversial fact about the increase in obesity is that it is entirely due to environmental changes of some sort. There’s disagreement on precisely which environmental changes, and on the likely public health impact, but not on the general principle. The reason is very simple: the genes of this generation’s children came from their parents, with almost no changes. There simply hasn’t been enough time for genetic differences to contribute.
The research paper is looking for mechanisms: they aren’t studying a representative population sample, but a group of 1500 children with severe obesity. Most of the genetic variants they found are very rare, and did not show up in the previous huge genetic study of weight and height that combined genetic data on quarter of a million people. That means these genetic variants can’t contribute much even to explaining or predicting which children are overweight. The last sentence of the research paper is illustrative of the point of the research
As we observed a significant enrichment for CNVs that deleted GPCRs, which are key targets for drug development, these findings may have potential therapeutic implications.
In English: there were lots of mutations that affected one particular type of cell signalling molecule, one that we’re pretty good at turning on and off with drugs. This could be useful.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »
We are indeed all mutants! The mutation rate is on the order of 2.5e-8 mutations per bp per cell division. With ~3e9 base pairs to mutate most of us are born with 50 — 100 new mutations Thankfully, most of our genome does nothing for us, so bad mutations, or even obesity-disposing ones are rarer.
11 years ago
Yes, that’s what I meant by “almost no changes”. It’s even more than that, I think, because a sperm cell arises from multiple divisions. There has been occasional news to the effect that older age at paternity means more new mutations per generation and the sky is falling.
And actually there are some diseases (eg autism) where de novo mutations do seem important — deletions, rather than point mutations.
11 years ago