Candidate genes for host association in aphids

新生物物种的起源依赖于阻止它们交配并产生成功后代的特征的进化。这一进化过程可能始于对新环境的适应，但这很少会造成完全的生殖障碍。如果发生了一些杂交，那么不直接参与适应不同栖息地的基因仍然可以共享。对于从这一点到完全防止杂交的进化是如何进行的，我们仍然知之甚少。在这个项目中，我们建议研究豌豆蚜虫，因为它的基因组已经被测序，并且已知它以几种不同的寄主植物为食，这些寄主植物代表着不同的环境。我们知道，蚜虫往往会与其他使用相同植物的人一起繁殖。这种趋势在某些情况下比其他情况下更强，所以我们有几个点可以比较新物种的进展。蚜虫使用化学线索来选择它们以哪种植物为食，我们现在知道了识别这些线索的基因类型。我们已经发现了其中一些基因，这些基因可能与使用不同植物的蚜虫之间的行为差异有关。在这个新的项目中，我们想找出这些基因是如何受到自然选择的影响的，以及它们是如何影响蚜虫寄主小种之间其他基因的共享的。我们还想找出在识别过程中使用了植物中的哪些化学物质。这将有助于我们了解物种的起源，也可能有助于控制作为农作物害虫的蚜虫。了解蚜虫是如何选择它们想要捕食的植物的，可以提供新的工具来防止蚜虫的危害。

The origin of new biological species depends on the evolution of characters that prevent them from mating and producing successful offspring. This evolutionary process may start with adaptation to new environments but this rarely creates a complete reproductive barrier. If some interbreeding occurs, then genes which are not directly involved in adaptation to different habitats can still be shared. We still have little understanding of how evolution proceeds from this point to the point of complete prevention of interbreeding.In this project, we propose to study the pea aphid because its genome has been sequenced and it is known to feed on several different host plant, which represent distinct environments. We know that aphids tend to reproduce with others that use the same plant. This tendency is stronger in some cases than others so we have several points on the progression towards new species that we can compare. Aphids use chemical cues to choose the plant on which they feed and we now know the types of genes underlying recognition of these cues. We have already found some of these genes that are likely to be involved in the differences in behaviour between aphids that use different plants. In this new project we want to find out how these genes are influenced by natural selection and how they affect the sharing of other genes between host races of aphids. We also want to find out which chemicals in the plants are used in the recognition process.This will help us to understand the origin of species and it may also help in control of aphids that are pests of crops. Understanding how aphids choose the plants they want to feed on can provide new tools to prevent aphid damage.