Laboratory of Evolutionary Genetics, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403;
Laboratory of Evolutionary Genetics, Institute of Ecology and Evolution, University of Oregon, Eugene, OR 97403.
Proc Natl Acad Sci U S A. 2018 Jan 30;115(5):1009-1014. doi: 10.1073/pnas.1717502115. Epub 2017 Dec 18.
The spread of blood-borne pathogens by mosquitoes relies on their taking a blood meal; if there is no bite, there is no disease transmission. Although many species of mosquitoes never take a blood meal, identifying genes that distinguish blood feeding from obligate nonbiting is hampered by the fact that these different lifestyles occur in separate, genetically incompatible species. There is, however, one unique extant species with populations that share a common genetic background but blood feed in one region and are obligate nonbiters in the rest of their range: Contemporary blood-feeding and obligate nonbiting populations represent end points of divergence between fully interfertile southern and northern populations. This divergence has undoubtedly resulted in genetic changes that are unrelated to blood feeding, and the challenge is to winnow out the unrelated genetic factors to identify those related specifically to the evolutionary transition from blood feeding to obligate nonbiting. Herein, we determine differential gene expression resulting from directional selection on blood feeding within a polymorphic population to isolate genetic differences between blood feeding and obligate nonbiting. We show that the evolution of nonbiting has resulted in a greatly reduced metabolic investment compared with biting populations, a greater reliance on opportunistic metabolic pathways, and greater reliance on visual rather than olfactory sensory input. provides a unique starting point to determine if there are universal nonbiting genes in mosquitoes that could be manipulated as a means to control vector-borne disease.
蚊子通过血液传播病原体依赖于它们吸血；如果没有叮咬，就不会传播疾病。尽管许多种蚊子从不吸血，但由于这些不同的生活方式发生在不同的、基因不相容的物种中，因此很难识别区分吸血和强制性不吸血的基因。然而，有一种独特的现存物种，其种群具有共同的遗传背景，但在一个地区吸血，而在其分布范围的其他地区则是强制性不吸血的：当代的吸血和强制性不吸血种群代表了完全可育的南方和北方种群之间分歧的终点。这种分歧无疑导致了与吸血无关的遗传变化，挑战在于剔除与吸血无关的遗传因素，以确定与从吸血到强制性不吸血的进化转变相关的遗传因素。在这里，我们确定了在一个多态种群中，由于对吸血的定向选择而导致的差异基因表达，以分离吸血和强制性不吸血之间的遗传差异。我们表明，与吸血种群相比，不吸血的进化导致代谢投资大大减少，对机会主义代谢途径的依赖更大，对视觉而不是嗅觉感官输入的依赖更大。这项研究为确定蚊子中是否存在普遍的不吸血基因提供了一个独特的起点，这些基因可以被操纵作为控制媒介传播疾病的一种手段。
