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2012-08-27. As Genes Learn Tricks, Animal Lifestyles Evolve

posted Sep 5, 2012, 4:30 PM by Alan Gould
| by Sean B. Carroll, The NY Times. An article relevant to GSS Losing Biodiversity chapter 4. Excerpt: Changes in the structure of the TRPA1 receptor, and the evolution of very high levels of expression in their sensory pits, endowed [snakes] with sensitive infrared detectors. The large evolutionary distance between pit vipers and pythons and boas indicates that the two groups of snakes separately evolved infrared sensing. But TRPA1 is not the only means of infrared sensing…blood-feeding bats also has sensory pits around the noses that the animals use to locate the warmest areas on the surface of their furry prey, where blood flow is the greatest…recruit[ing] a different ion channel/ receptor called TRPV1 to become an infrared sensor. What is especially noteworthy about TRPV1 is that it is the very same receptor that detects capsaicins, the active ingredients in chili peppers, in our neurons. It causes the familiar burning sensation when prompted… scientists discovered that the particular form of the receptor expressed in vampire bat trigeminal neurons was much more heat-sensitive (by about 9 degrees Celsius) than either our TRPV1 receptor or the TRPV1 expressed in fruit bat neurons. The vampire bat receptor is thus tuned to detect heat in ways that other bats and mammals cannot. Both the TRPA1 and TRPV1 genes are hundreds of millions of years old, having arisen deep in evolutionary history, while vampire bats, pit vipers, and pythons and boas are much younger species. The histories of these genes and animals, and the repeated invention of infrared sensing, demonstrate how the evolution of new abilities does not necessarily require new genes, but new variations of very old genes and new ways of using them…. Read the full article: http://www.nytimes.com/2012/08/28/science/animals-lifestyles-evolve-when-old-genes-learn-new-tricks.html?ref=science