Slashdot Mirror
All Humans Are Mutants, Say Scientists
Hugh Pickens writes "In 1935, JBS Haldane, one of the founders of modern genetics, studied a group of men with the blood disease hemophilia and speculated that there would be about 150 new mutations in each human being. Now BBC reports that scientists have used next generation sequencing technology to produce a far more direct and reliable estimate of the number of mutations by looking at thousands of genes belonging to two Chinese men who are distantly related, having shared a common ancestor who was born in 1805. To establish the rate of mutation, the team examined an area of the Y chromosome which is unique because, apart from rare mutations, the Y chromosome is passed unchanged from father to son so mutations accumulate slowly over the generations. Despite many generations of separation, researchers found only 12 differences among all the DNA letters examined. The two Y chromosomes were still identical at 10,149,073 of the 10,149,085 letters examined."
Y = 1/300th total chromosome
3600 mutations total
8 generations in 200 years
450 per generation
5 in protein coding section of genome
Rather than making me think that all humans are mutants, this made me think: Wow, over a runtime of 204 years, the DNA copying process has an accuracy of 99.99988%, or an error rate of only 0.00012%.
I think we'll be hard-pressed to replicate that level of awesomeness in computers anytime soon.
Alphanos
SMBC is completely accurate on this count.
Yep, it's obvious that we're all mutants, how else does evolution happen? The bbc seems to have missed the point, which to me is that they've now got a decent (they claim) estimate of the rate of mutation. This is, however infinitely less interesting than the bbc title.
Basically, they should be looking at the men that are from the same place (assuming that one of the two live in the exact same area and others ppl can be found). I think that they will find many of them have the same sets of mutations. The reason is that I believe that many of these mutations are from virus, not from random mutations. If from radiation/chemical (i.e. random), then you will not see the same mutations across ppl that exist in same area. But if from virus, you will see that many of these are similar (though possibly not in the exact same area of the strands).
I prefer the "u" in honour as it seems to be missing these days.
Yeah, the "all humans are mutants" angle doesn't have much to it. Of course we're mutants insofar as we're the product of evolution, and evolution requires mutation. Without mutation, you wouldn't get new genetic differences to be weeded out or passed on. So yes, life is a mutation and we're all mutants.
It will be interesting now that we could be able to sequence your DNA and your parents' DNA, figure out exactly what mutations you have (if any) from the previous generation, and possibly know what those mutations do. Maybe in the future we'll be able to map all of our genetic family trees in detail, figure out when traits were introduced, and see what patterns emerge. Maybe those random mutations aren't so random.
The Y chromosome doesn't get to recombine, so measuring the mutation rate of the Y chromosome only gives us a limited understanding of mutations in general.
Lack of recombination means you don't get to measure mutations that consist of genes being brought together for the first time in an individual. It also eliminates entire classes of accidental mutations. On the other hand, it removes the opportunity for some types of in-cell DNA repair.
Furthermore, the Y chromosome is less interesting than most. It contains very few working genes, precisely because it is not subject to the most important DNA repair mechanism of all: sexual reproduction.
The shareholder is always right.
Maybe those random mutations aren't so random.
This is complicated and not really worth going into in depth here, but a major technique of mapping species divergence and establishing when they diverged is through mapping the number of mutations that have shown up in non-expressed DNA. The mutation rate of DNA is fairly well known (it's largely a function of the precision of the enzymes that duplicate DNA, the DNA polymerases and their error-correction fidelity, which varies between different DNA polymerases.) There are some wrinkles in that many mutations don't survive -- they're lethal -- and that's why some parts of DNA are referred to as 'conserved', because those sections can't tolerate changes. There are genes involved in vision, for instance, that have something like a 0.3% difference between insects and humans. But sections that aren't critical, or aren't used at all, chunks of old viruses that got spliced in and don't do anything, accumulate errors. Taking a quantitative diff of two DNA strants gives you a number that is proportional to how long ago the species diverged.
Nostalgia's not what it used to be.