| 翻訳と辞書 |
| Bitter taste evolution ： ウィキペディア英語版 |
Bitter taste evolution
One of the most dynamic evolutionary adaptations to arise in multiple species has been the evolution of bitter taste receptors. This phenomenon has been widely studied in the field of evolutionary biology because of its role in the identification of toxins often found on the leaves of inedible plants. A palate more sensitive to these bitter tastes would, theoretically, have an advantage over members of the population less sensitive to these poisonous substances because they would be much less likely to ingest toxic plants. Bitter taste genes have been found in a variety of species, and the same genes have been well characterized in several common laboratory animals such as primates and mice, as well as in humans. The primary gene responsible for encoding this ability in humans is the TAS2R gene family which contains 25 functional loci as well as 11 pseudogenes. The development of this gene has been well characterized, with proof that the ability evolved before the human migration out of Africa.〔Risso, et al. 2014. Genetic variation in taste receptor pseudogenes provides evidence for a dynamic role in human evolution. BMC Evolutionary Biology. 14:1-23.〕 The gene continues to evolve, for better or for worse, in the present day.
== TAS2R ==
The bitter taste receptor family, T2R (TAS2R), is encoded on two chromosomes, 7 and 12. Genes on the same chromosome have shown remarkable similarity with each other, suggesting that the primary mutagenic forces in evolution of TAS2R are duplication events. These events have occurred in at least 7 primate species: chimpanzee, bonobo, human, gorilla, orangutan, rhesus, and baboon.〔Fischer, et al. 2004. Evolution of Bitter Taste Receptors in Humans and Apes. Molecular Biology and Evolution. 22:432-436.〕 The high variety among primate and rodent populations additionally suggests that, while selective constraint on these genes certainly exists, its effect is rather low.
Members of the T2R family encode alpha subunits of G protein coupled receptors, which are involved in intracellular taste transduction, not only on the taste buds but also in the pancreas and gastrointestinal tract. The mechanism of transduction is shown by exposure of the endocrine and gastrointestinal cells containing the receptors to bitter compounds, most famously phenylthiocarbamide (PTC). Exposure to PTC causes an intracellular cascade as evidenced by a large and rapid increase in intracellular calcium ions.〔Wu et al. 2001. Expression of bitter taste receptors of the T2R family in the gastrointestinal tract and enterendocrine STC-1 cells. Proceedings of the National Academy of Sciences of the United States of America. 99:2392-2397.〕
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Bitter taste evolution」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|