quote:
By the way, where are the useful mutations?
I have a useful mutation.
I have a mutation that prevented two (the lower pair) of my wisdom teeth from developing.
As I naturally had pretty crooked teeth (braces) and had to have teeth pulled in my upper jaw to make room for everything, there was a space for upper wisdom teeth.
The lower ones may or may not have fit in, and I might have had to suffer the pain of impaction, and then had to have oral surgery to extract them, etc.
Instead, the lower teeth don't exist at all, and it turns out that this is due to a mutation in the MSX1 gene. It is a mutation which occurs in around 10 percent of the population, and varies in how many teeth are missing. I got lucky and I had a benefit conferred, but others with this mutation can be missing many of their molars, for example.
Here's some more info.
link
MSX1 belongs to the homeobox genes, which encode proteins that set up basic body patterns. Teeth, much like limbs, form according to a genetically determined pattern that is much the same in all humans. We all have the same number of teeth; they all erupt in the same location, and even a casual observer can tell an incisor from a canine or a molar. "So it was intriguing that mapping the entire genome landed us in a region where a previously defined patterning factor resided," says Seidman.
The next obvious step-sequencing this candidate gene-turned up a mutation in affected individuals. This mutation leads to the exchange of a single amino acid in the very region of the protein that is crucial to its function as a transcription factor. That region, called the homeodomain, is where the protein latches onto specific spots on the DNA and activates other genes necessary for the formation of the desired pattern. Evolution has conserved that area of the protein-almost to the amino acid-across frogs, chickens, mice, and humans, making it all the more likely that a mutation meddling with that part of the protein may have drastic consequences, says Seidman.
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