General > Biology
human mutation rate
ikke:
I came across this article claiming people have about 100 to 200 mutations per generation. To me this seems high. Even if only 5% of the genome is functional this means on average the genome breaks in 5-10 places
http://news.bbc.co.uk/2/hi/8227442.stm
Numsgil:
Keep in mind how many embryos that are fertilized never result in a viable pregnancy. Not just miscarriages, but "pregnancies" of only a week or less that we never really know about. So there's a bit of a survivor's bias.
Maybe there's also some intelligent mutation-ing going on. Maybe some parts of the genome are allowed to mutate more than other parts.
ikke:
--- Quote from: Numsgil on February 04, 2011, 01:05:41 PM ---Keep in mind how many embryos that are fertilized never result in a viable pregnancy. Not just miscarriages, but "pregnancies" of only a week or less that we never really know about. So there's a bit of a survivor's bias.
--- End quote ---
Sure, this begins with the sperm's rat race to fertilize. But estimates of spontaneous abortions are only (only is used in terms of the 5-10 mutations in functional code) in the 10-25% range. With half the women pregnant within 3-4 months these numbers don't seem to add up. I have to admit I haven't done any math and probabilities are hard to estimate beyond the simple draw
--- Quote from: Numsgil on February 04, 2011, 01:05:41 PM ---Maybe there's also some intelligent mutation-ing going on. Maybe some parts of the genome are allowed to mutate more than other parts.
--- End quote ---
For me this means either the code is non functional and already discounted in the 95% mutations in junk or it is redundant, with other code partly or entirely absorbing loss of functionality
Billy:
Perhaps most genes are repeated many times to maximize their effect. If one gene is ruined, there would probably be little impact because it would only mean a small amount less of whatever protein the gene is supposed to encode.
ikke:
I just did the quick math: assuming 150 mutations per generation and 95% of DNA non functional the probability of not having a single mutation in functional DNA is 1-.95^150 (assuming random spread of mutations through the DNA. This is a one in 2200 chance.
--- Quote from: Numsgil on February 04, 2011, 01:05:41 PM ---Maybe there's also some intelligent mutation-ing going on. Maybe some parts of the genome are allowed to mutate more than other parts.
--- End quote ---
I just realised I omitted DNA correction mechanisms. They may have enormous impact on the probability of mutations occurring in functional vs in non functional DNA. This would invalidate my random spread mutations assumption.
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