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Religious Ceremony Leads To Evolution of Cave Fish
An anonymous reader writes "A centuries-old religious ceremony of an indigenous people in southern Mexico has led to evolutionary changes in a local species of fish, say researchers at Texas A&M University. Apparently since before Columbus arrived, the Zoque people would venture each spring into the sulfuric cave Cueva del Azufre to beg the gods for bountiful rain. As part of the ritual, they released into the cave's waters a leaf-bound paste made of lime and the ground-up root of the barbasco plant, a natural fish toxin. The rest is worth reading, but the upshot is that the fish living in the cave waters eventually got wise, genetically speaking."
The Peppered Moth is a famous example, but a dreadful one. There are several problems with Kettlewell's experiment, many of which are pointed out here: Second Thoughts about Peppered Moths
It's one rock-fall blocking the river away from that happening. Population isolation happens.
Indeed the paper talks about a "potential effect on gene flow" ("Our findings reveal potential effects of an indigenous cultural practice on three distinct processes: (i) dynamics within affected populations, (ii) gene flow among populations, and (iii) adaptive trait divergence between affected and unaffected populations.") Scientists are nothing if not careful.
Still the fact that this is an annual event with a high dose poisening instead of gradual long term exposure makes mithridization unlikely (IMHO, not a biologist.) The paper says : "barbasco is deposited inside the cave about 100 m from the cave entrance, from where it is distributed downstream and outside of the cave." so the poison would be washed out.
I see the guy has some of these fish in his tanks so hopefully he'll do a follow-up with specimens from the different populations bred in captivity under controlled conditions.
If all else fails, immortality can always be assured by spectacular error.