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Comment by nyc111 | Hacker News Reader

In the Science article they wrote, “Poaching resulted in strong selection that favored tusklessness amid a rapid population decline.” And, “Whole-genome scans implicated two candidate genes with known roles in mammalian tooth development (AMELX and MEP1a), including the formation of enamel, dentin, cementum, and the periodontium.”

So, there was a change in the genes, but how do they connect this fact with poaching? I don’t see the relation. Surely, elephants themselves, cannot decide to change their genetics as a reaction to poaching.

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It's not like evolution detects this. If you kill off all the blond headed people in town, all the babies next year will be born with brown hair. The tuskless variant was already in the population at some proportion, but due to tusks being a target of poaching, those that carry the tuskless variant are more likely to survive and have offspring, who are also going to have this tuskless variant. Over time, the population will shift and this tuskless variant will be present at a higher proportion in the overall population.

> If you kill off all the blond headed people in town, all the babies next year will be born with brown hair.

The blond hair allele is recessive and can be hidden. Two brown-haired parents can have a blond child.

> how do they connect this fact with poaching?

Poachers kill elephants for their tusks. A poacher won't kill an elephant with partially formed or no tusks, as it has no value to them. This allows elephants with the tuskless gene to survive and eventually reproduce where other elephants would not.

It's artificial* selection. The ones with husks die** more often before having offsprings, or will on average get to have fewer offsprings, in comparison to the tuskless individuals.

*) Humans are putting the pressure.

**) Are killed by poachers.

Evolution works thanks to natural pressures -- in this case, a mutation in the gene gives an elephant no tusks, and thanks to this they are not killed by poachers. That elephant is lucky enough to survive to pass on its DNA. The recessive gene, over many generations, grows more dominant as more and more elephants "benefit" from having no tusks by not being hunted.

So the elephants aren't reacting to poaching -- the "reaction" is a random mutation that happens to align with external pressures, causing a shift in genetics for the population.

Random mutations happen all the time. If there’s selection pressure that favors a given mutation, it will proliferate.

Just throwing it out there; i know it's scientifically accepted that genetic mutations are simply random and the ones that just so happen to be helpful are propagated by natural selection, but i sometimes wonder that 'random' is a word akin to 'magic' that describes a process we do not quite understand. Specifically in the context of evolution, i wonder if genetic mutations aren't as random as we believe it to be, but that life is more 'intelligent' than we give it credit for, and mutations are, if not always at least sometimes, an intentional response to changes in their environment. I'd be very interested to see more research in the way that genetic mutations may be influenced by external stimuli.

Not an idea i deeply hold as a truth, but fun to think about, and science doesn't expand by believing we've got it all figured out.

Surely? I wouldn't discount the power of intention when applied to the all too common occurrence of deep emotional stress of experiencing the loss of your family in such a violent display.

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