Evolution by Religious Selection: Mexican Cavefish Develop Resistance to Toxin
ScienceDaily (Nov. 5, 2010) — A centuries-old religious ceremony of an indigenous people in southern Mexico has led to small evolutionary changes in a local species of fish, according to researchers from Texas A&M University.
Top: Atlantic molly. Bottom: Ceremony in the Cueva del Azufre. (Credit: Michael Tobler (top); Mona Lisa Productions (bottom))
Since before the arrival of Christopher Columbus to the New World, the Zoque people of southern Mexico would venture each year during the Easter season deep into the sulfuric cave Cueva del Azufre to implore their deities for a bountiful rain season. As part of the annual ritual, they release into the cave's waters a distinctive, leaf-bound paste made of lime and the ground-up root of the barbasco plant, a natural fish toxin. Believing the cave's fish to be gifts from their gods, they scoop up their poisoned prey to feed upon until their crops are ready to harvest.
However, a team of researchers led by Dr. Michael Tobler, an evolutionary ecologist at Oklahoma State University, and Dr. Gil Rosenthal, a biology professor at Texas A&M, has discovered that some of these fish have managed not only to develop a resistance to the plant's powerful toxin, but also to pass on their tolerant genes to their offspring, enabling them to survive in the face of otherwise certain death for their non-evolved brethren.
Their findings recently were published in the online journal Biology Letters.
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An indigenous religious ritual selects for resistance to a toxicant in a livebearing fish
M. Tobler1,3,*†, Z. W. Culumber2,3, M. Plath4, K. O. Winemiller1 and G. G. Rosenthal2,3
+Author Affiliations
1Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
2Department of Biology, Texas A&M University, College Station, TX 77843, USA
3Centro de Investigaciones Científicas de las Huastecas ‘Aguazarca’, Calnali, Hidalgo, Mexico
4Department of Ecology and Evolution, J. W. Goethe University, 60054 Frankfurt am Main, Germany
*Author for correspondence (michi.tobler@gmail.com).
Abstract
Human-induced environmental change can affect the evolutionary trajectory of populations. In Mexico, indigenous Zoque people annually introduce barbasco, a fish toxicant, into the Cueva del Azufre to harvest fish during a religious ceremony. Here, we investigated tolerance to barbasco in fish from sites exposed and unexposed to the ritual. We found that barbasco tolerance increases with body size and differs between the sexes. Furthermore, fish from sites exposed to the ceremony had a significantly higher tolerance. Consequently, the annual ceremony may not only affect population structure and gene flow among habitat types, but the increased tolerance in exposed fish may indicate adaptation to human cultural practices in a natural population on a very small spatial scale.
adaptation, anthropogenic disturbance, barbasco, cavefish, rotenone, Poecilia mexicana
Footnotes
↵† Department of Zoology, Oklahoma State University, Stillwater, OK 74078, USA
Received July 20, 2010.
Accepted August 17, 2010.
© 2010 The Royal Society
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NOTA DESTE BLOGGER:
Um caso de seleção artificial e não de seleção natural: apenas variação natural e dinâmica populacional.
Sendo caso de seleção artificial, a pesquisa está mais para design inteligente do que evolução gradualista darwiniana.
Fui, nem sei por que, pensando que muitos cientistas evolucionistas estão precisando imediatamente de um curso de Lógica 101...
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NOTA DESTE BLOGGER:
Um caso de seleção artificial e não de seleção natural: apenas variação natural e dinâmica populacional.
Sendo caso de seleção artificial, a pesquisa está mais para design inteligente do que evolução gradualista darwiniana.
Fui, nem sei por que, pensando que muitos cientistas evolucionistas estão precisando imediatamente de um curso de Lógica 101...
