American biologists have analyzed twelve different species of carnivorous mammals, came to the conclusion that many of them have lost the ability to feel the sweet taste.
The researchers conducted a sequencing of the gene Tas1r2, belonging to different mammalian origins, united exclusively meat diet, writes. Lenta. ru. Among them were bottlenose dolphins, sea lions, muskrat, spectacled bear, the Madagascan Fossa and aardwolf. It was found that many of these genes responsible for sensitivity to sweet, turned into a pseudogene, ie, lost the ability to encode a protein synthesis.
Changes in the sequence that caused the loss of functionality of the gene in different animals, were different. This means that the loss of sensitivity to sweet place in the case of each animal, regardless.
Earlier, the same authors published a paper in which he showed at the dysfunctionality of the gene Tas1r2 cat. The mutations were common to the entire family, so it was not clear whether this is a random feature of the cat or is related to the food ration. Now the authors may argue that the loss of sensitivity to sweet is a typical example of convergent ( reconciling ) the evolution of.
Sugars are mainly in plant foods, so the predators who do not use it, the ability to feel the sweet is not needed. Selection pressure on otbrakovyvanie mutation was absent that, apparently, and led to its dysfunctionality.
Scientists have found that some of the animals examined had lost the ability to recognize not only the sweet. For example, bottlenose dolphins and sea lions have lost the ability to feel the MSG is responsible for ... Bottlenose dolphins, in addition, have lost the ability to detect bitter. Zoologists point out that this is probably due to their eating behavior - in fact they swallow food, do not chew it.
Source: focus. ua.
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