Dissertation Research: The Evolution of Disease Susceptibility

动物如何在抵御疾病的需要和生长或繁殖等其他需要之间取得平衡？一种可能性是，一种如此昂贵的努力是通过与另一种努力的权衡来实现的。为了研究这种权衡的作用，这项研究测试了建立抗微生物免疫反应是否在能量上耗资巨大，这些成本是否影响个体生存和繁殖的能力，最后，这种拟议的权衡是否有遗传基础。这项研究是利用果蝇黑腹果蝇进行的，果蝇是研究遗传学、生活史和昆虫免疫的模式系统。通过比较免疫反应和测量在实验室培育的特定遗传特征的苍蝇的免疫成本，可以测量抗病能力的进化。寄生虫和疾病在自然种群中普遍存在，寄生虫会降低宿主的生存和繁殖能力。因此，人们可能会期待进化出对病原体的强大防御能力，但在许多不同的生物体中，对疾病的易感性仍然很高。这个问题的一个解决方案是，抗药性代价高昂，并以动物的生存和繁殖能力为代价。这项研究将有助于我们理解这种权衡在维持疾病易感性方面所起的作用。

Zuk9902305How do animals balance the need for defense against disease against other needs such as growth or reproduction? One possibility is that one such costly effort is achieved by a trade-off with another. To investigate the role of such trade-offs, this research tests whether mounting an anti-microbial immune response is energetically costly, whether these costs affect the ability of individuals to survive and reproduce, and lastly, whether this proposed trade-off has a genetic basis. This research is being carried out using the fruit fly Drosophila melanogaster, a model system for the study of genetics, life history, and insect immunity. By comparing immune responses and measuring costs of immunity in flies that have been bred in the laboratory for specific genetic traits, the evolution of disease resistance can be measured. Parasites and disease are ubiquitous in natural populations, and parasites can decrease both the survival and reproductive ability of their hosts. One might therefore expect evolution of strong defenses against pathogens, yet susceptibility to disease remains high in many different organisms. One solution to this problem is that resistance is costly and trades off with an animal's ability to survive and reproduce. This research will contribute to our understanding of the role that such trade-offs play in maintaining disease susceptibility.