DISSERTATION RESEARCH: Quantitative Genetics of Innate Immunity in Drosophila Melanogaster

对各种生物体的大量研究已经确定，不同个体之间的免疫功能存在广泛的差异。 果蝇（Drosophila melanogaster）为研究这种变异的潜在遗传基础提供了一个有用的模型系统。 理解复杂性状（如免疫功能）遗传变异的一个关键组成部分是破译这种变异中有多少代表了加性变异，这决定了一种性状的进化速度。 本研究采用标准杂交设计，对D.黑腹菌，以及在免疫途径中表达关键候选基因的加性遗传变异。 除了预测未来变异将如何对选择做出反应外，加性遗传变异的模式还可以用来推断可能作用于我们观察到的遗传变异的进化力量。 因此，了解果蝇免疫系统中的加性遗传变异的程度将有助于确定免疫系统中的功能变异是否是由于多效性效应，其中对免疫功能的某些方面有益的变异对其他性状具有负面影响，或者免疫系统中的功能变异是否是由于群体中低频率分离的有害突变。 这些结果将对理解免疫系统如何进化，以及进化力量如何塑造关键适应性特征的变化产生影响。

Considerable research in a wide variety of organisms has established that there is extensive variation for immune function among different individuals. The fruit fly, Drosophila melanogaster, provides a useful model system for studying the underlying genetic basis for that variation. A key component of understanding genetic variation for complex traits such as immune function is deciphering how much of that variation represents additive variation, which determines how rapidly a trait can evolve. By using standard crossing designs, this work will measure the additive genetic variation for immune system function in D. melanogaster, as well as additive genetic variation for expression of key candidate genes in the immune pathway. In addition to predicting how variation will respond to selection in the future, patterns of additive genetic variation can be used to infer the evolutionary forces that have likely acted on the genetic variation we observe. Therefore, understanding the extent of additive genetic variation in the Drosophila immune system will help determine whether functional variation in the immune system is due to pleiotropic effects, where variants that are beneficial for some aspect of immune function have negative consequences for other traits, or whether functional variation in the immune system is due to deleterious mutations segregating at low frequency in the population. These results will have implications for understanding how immune systems evolve, and how evolutionary forces shape variation in crucial fitness traits.