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Comment by shevy-java | Hacker News Reader

So Lamarck wasn't entirely incorrect either. Darwin would have been fascinated by these results.

There has been aruably a more serious blow to the pure Darwinian evolution (this is all epigenetics, after all): non-random occurrence of useful mutations in populations exposed to particular diseases.

https://pubmed.ncbi.nlm.nih.gov/40854136/

I don’t really see that as anti-Darwinian. Those genes successfully attach themselves to a new organism and provide advantages such that they are selected for in the population.

The selection is classical, but the mutations are supposed to be random, not skewed towards more useful genetic variants. One can speculate that a purely random (and otherwise neutral, say) prior mutation led to this directionality, but the actual resulting mechanism is AFAIK still unknown.

plasmids

https://en.wikipedia.org/wiki/Plasmid

Natural selection has nothing to do with randomness per se, it’s merely differential selection based on environmental fitness. The fitness function of a given environment can even narrow a range of existing genes without any mutation occurring during the period where the new fitness function is applied. The classic example of this is peppered moths shifting toward the darker range of their preexisting color range during the Industrial Revolution.

Horizontal gene transfer is another way organisms can acquire new traits.

I don't think Darwin himself said anything about the randomness of the mutations, and of course was not aware of DNA and how things were encoded. I guess followers of Darwin may have said all sorts of things but the paper doesn't seem to contradict Darwinian evolution as described by Darwin.

I see the paper says "central tenet of neo-Darwinism that mutations are random...". I'm not that up on neo-Darwinism whatever it is.

(I looked at Wikipedia and it seems neo-Darwinism is the term for the Darwin like thinking of the time so maybe the paper contradicts last years neo-Darwinism but not next years?)

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.

Lysenko wasn't entirely wrong then, crazy.

It's clear that purely random mutations don't work in the sense that an infinite number of monkeys won't produce Shakespeare even if you kill of the monkeys that fail.

The monkeys would write Shakespeare if you tested their output character by character instead of waiting till the end. That's how evolution works too - in tiny cumulative achievable steps.

I'm not sure of the maths there. The number of letter permutations of a Shakespeare play is ~10^400000 and infinity is bigger than that. Though you might have a job feeding the monkeys.

In Lamarkian evolution features that organisms use either accentuate or attenuate. That's not how epigenetics works in general.

Even if this was going to hold up, it wouldn't make the policies that Lamarck's ideas were designed to promote work. We already empirically know they don't work.

viewing genetics as dogmatic darwinist purity isnt the state of the art.

current genetic theory is a synthesis, loosely referred to as neo-darwinism

https://en.wikipedia.org/wiki/Neo-Darwinism

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