捕食者と獲物の軍拡競争における適応メカニズム:TTX耐性ナトリウムチャネル
Shana Geffeney1, Edmund D Brodie, Peter C Ruben
1Department of Biology, Utah State University, Logan, UT 84322, USA.
Science (New York, N.Y.)
|August 24, 2002
まとめ
紐蛇 (Thamnophis sirtalis) は,筋肉内の変異したナトリウムチャネルを通じて,新毒テトロドトキシン (TTX) に対する異なる耐性を進化させた. この生理学的適応が,有毒な獲物との共進化的軍拡競争を駆り立てている.
科学分野:
- 進化生物学の進化生物学について
- 毒理学 毒理学 毒理学
- 分子生理学 分子生理学
背景:
- 帯蛇 (Thamnophis sirtalis) は,テトロドトキシン (TTX) に対して地理的に異なる耐性を示す.
- この抵抗は,彼らの獲物である有毒な新 (Taricha属) との共進化的軍拡競争の一部です.
研究 の 目的:
- Thamnophis sirtalis.におけるTTX耐性における適応的多様化の背後にある生理学的メカニズムを特定する.
- 集団レベルでの共進化的動態を分子的,生理学的適応と結びつける.
主な方法:
- Thamnophis sirtalisの骨格筋におけるナトリウムチャネルの発現を調査した.
- 筋肉繊維のTTX抵抗と全動物抵抗の相関した個人および集団の差異.
主要な成果:
- 骨格筋におけるTTX耐性ナトリウムチャネルの発現を重要な生理学的メカニズムとして特定した.
- TTXにおける筋肉繊維機能と,動物全体のTTX耐性との間には密接な相関があることがわかりました.
結論:
- TTX耐性ナトリウムチャネルの変動が,紐蛇の集団の適応的多様化に根底にあることを実証した.
- これは,共進化の相互作用と地理的多様性のパターンとの間のメカニズム的なリンクを提供します.
関連する概念動画
00:48Optimal Foraging
How animals obtain and eat their food is called foraging behavior. Foraging can include searching for plants and hunting for prey and depends on the species and environment.
01:32What is Natural Selection?
Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become more common within a population or species. Naturally selected traits initially arise via random genetic mutations. In order for selection to occur, there must be variation within a population, the trait controlling the variation must be heritable, and there must be an evolutionary advantage for variation in the trait.The Theory of Natural...
02:34Competition
When organisms require the same limited resources within an environment, they may have to compete for them. Competition is a net-negative interaction. Even if two competing individuals or populations do not interact directly, the overall fitness of both competitors is lowered as a result of not having full access to the limited resource.Intraspecific competition, which occurs between individuals of the same species, serves as a natural mechanism for regulating population size. Too much...
02:39Predator-Prey Interactions
Predators consume prey for energy. Predators that acquire prey and prey that avoid predation both increase their chances of survival and reproduction (i.e., fitness). Routine predator-prey interactions elicit mutual adaptations that improve predator offenses, such as claws, teeth, and speed, as well as prey defenses, including crypsis, aposematism, and mimicry. Thus, predator-prey interactions resemble an evolutionary arms race.Although predation is commonly associated with carnivory, for...
01:15Natural Selection and Adaptation
Natural selection, a fundamental concept in evolutionary biology, is the mechanism by which evolution is driven, favoring organisms that are best adapted to their environments. This process enhances their chances of survival and reproduction. Adaptation, a key outcome of this process, involves genetic modifications that optimize an organism's functionality under specific environmental challenges, such as extreme cold or thinner air at high altitudes.
Beyond physical adaptations, psychological...
Beyond physical adaptations, psychological...
01:16Transduction
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome are...