在與有毒的獵物粗皮蠑螈進(jìn)行的“軍備競(jìng)賽”中,，西部襪帶蛇成為了最后的贏家（如圖）,。
據(jù)美國(guó)《科學(xué)》雜志在線報(bào)道,，隨著時(shí)間的推移,，蠑螈逐漸進(jìn)化出了毒性—— 一只蠑螈足以毒死幾個(gè)成年人,，而蛇對(duì)這種毒性的抵抗能力則也變得越來(lái)越強(qiáng)。將近1/3的美國(guó)西部襪帶蛇能夠承受蠑螈的毒性,。這種保護(hù)功能主要依賴于一個(gè)與離子通道有關(guān)的基因產(chǎn)生的突變,，從而防止該通道因毒素的作用而關(guān)閉，并且由此產(chǎn)生了一個(gè)蠑螈難以企及的強(qiáng)大的免疫系統(tǒng),。研究人員在最近的《科學(xué)公共圖書館·生物學(xué)》（PLoS Biology）網(wǎng)絡(luò)版上報(bào)告了這一研究成果,。（來(lái)源：科學(xué)時(shí)報(bào) 群芳）
生物谷推薦原始出處：
（PLoS Biology），doi:10.1371/journal.pbio.0060060,，Charles T. Hanifin, Edmund D. Brodie Jr., Edmund D. Brodie III
Phenotypic Mismatches Reveal Escape from Arms-Race Coevolution
Charles T. Hanifin1¤*, Edmund D. Brodie Jr.1, Edmund D. Brodie III2
1 Department of Biology, Utah State University, Logan, Utah, United States of America, 2 Department of Biology, University of Virginia, Charlottesville, Virginia, United States of America
Because coevolution takes place across a broad scale of time and space, it is virtually impossible to understand its dynamics and trajectories by studying a single pair of interacting populations at one time. Comparing populations across a range of an interaction, especially for long-lived species, can provide insight into these features of coevolution by sampling across a diverse set of conditions and histories. We used measures of prey traits (tetrodotoxin toxicity in newts) and predator traits (tetrodotoxin resistance of snakes) to assess the degree of phenotypic mismatch across the range of their coevolutionary interaction. Geographic patterns of phenotypic exaggeration were similar in prey and predators, with most phenotypically elevated localities occurring along the central Oregon coast and central California. Contrary to expectations, however, these areas of elevated traits did not coincide with the most intense coevolutionary selection. Measures of functional trait mismatch revealed that over one-third of sampled localities were so mismatched that reciprocal selection could not occur given current trait distributions. Estimates of current locality-specific interaction selection gradients confirmed this interpretation. In every case of mismatch, predators were “ahead” of prey in the arms race; the converse escape of prey was never observed. The emergent pattern suggests a dynamic in which interacting species experience reciprocal selection that drives arms-race escalation of both prey and predator phenotypes at a subset of localities across the interaction. This coadaptation proceeds until the evolution of extreme phenotypes by predators, through genes of large effect, allows snakes to, at least temporarily, escape the arms race.
