Comment by skissane
5 hours ago
I wonder how that works? Speculation: there is some kind of genetic/epigenetic signalling which modulates DNA repair mechanisms, such that certain DNA regions can be marked as more mutation-prone than others. And there may be selective pressure to make genes associated with disease-resistance more mutation-prone, because that’s a gene whose mutation is more likely to be beneficial (compensating mutations for evolution in existing diseases or to respond to new diseases), less likely to be harmful (most of the time, most likely outcome of the “wrong” mutation would be less resistance to diseases, but it probably wouldn’t otherwise be lethal or cause serious disability). But if that is what is actually going on here, is there any actual challenge to Darwin’s views? He didn’t know about DNA; I don’t think he ever claimed all mutations were equally likely (why would he when he had no idea what the actual mechanisms behind them were)
darwin had the idea that many individuals with variation were culled according to relative fitness.
mendel later demonstrated that this variation was passed fractionally, to decendants. this was a conserved probability of fixed combinations [consult "mendels peas" ]
the two taken together resulted in neo-darwinist mechanisms. darwin was not wrong, mendel was less wrong, contemporarily we are still scratching the surface of getting it right, primarily what rules apply to what groups, what mechanisms are conserved, what combinations of functions are served by a particular structure, departing from the one gene one function hypothesis.