Translational control in homoeobox mRNAs?
Translational control in homoeobox mRNAs?
复制标题
同源框 mRNA 的翻译控制？
作者：
T. Bürglin;Christopher V. E. Wright;E. Robertis
StR-McAllister和Roitberg最近报道了豌豆蚜虫（Acyrthosiphon pisum）的“适应性自杀”证据。蚜虫有三种逃避捕食者的策略：后退、逃跑和从食物植物上掉下来。来自干旱地区的寄生蚜虫比预期更经常地使用下降策略，这被认为是自杀行为。作者试图排除这种明显的自杀行为是寄生虫直接适应不良的可能性：他们比较了沿海和干燥栖息地的蚜虫的行为，在那里下降的健康后果是不同的。然而，实验原理依赖于毫无根据的假设，即两个蚜虫种群在不参与反捕食行为的基因座上是遗传同质的。事实上，在以前的一篇论文中，含蓄地说，生活在沿海和干旱两个地区的蚜虫”被认为是不同的生物型”。因此，来自干燥栖息地的蚜虫可能更容易受到寄生虫的直接影响。所用的蚜虫只被来自其栖息地的黄蜂寄生。因此，观察到的蚜虫种群之间的差异可能是寄生虫的功能，而不是主机。可以使用所有四种宿主/寄生虫组合进行标准化实验来检查这种可能性。来自炎热地区的寄生蚜虫的坠落行为增加可能只是逃避捕食者的一种上级手段。作者给出了一个不精确的指示健身的后果，不同的逃生策略，在两个蚜虫栖息地。此外，他们没有表明是否寄生和未寄生的个人之间的健身后果不同。
StR-McAllister and Roitberg'recently reported evidence for'adaptive suicide''in pea aphids (Acyrthosiphon pisum). The aphids were said to have three strategies of escape from predators: backing-up, running, and falling from the food plant. Parasitized aphids from dry regions used the falling strategy more often than expected and this was put forward as suicidal behaviour. The authors attempted to exclude the possibility that the apparently suicidal behaviour was a direct maladaptive effect of the parasite: they compared the behaviour of aphids from coastal and from dry habitats, where the fitness consequences of falling were different. However, the experimental rationale relies upon the unfounded assumption that the two aphid populations were genetically homogeneous at loci not involved in antipredator behaviour. Indeed, in a previous paper', it is implicitly stated that aphids living in two areas, coastal and dry," are considered different biotypes". Therefore, aphids from the dry habitat may simply be more susceptible to the direct effects of the parasite.The aphids used were only parasitized by wasps from their own habitat. Therefore, the observed differences between aphid populations may have been a function of the parasites rather than the hosts. A standardized experiment using all four host/parasite combinations could be performed to examine this possibility. The increased falling behaviour of parasitized aphids from hot regions may simply be a superior means of escape from predators. The authors give an imprecise indication of the fitness consequences of different escape strategies in each of the two aphid habitats. Moreover, they do not indicate whether the fitness consequences differ between parasitized and unparasitized individuals.