Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island, USA.
PLoS Genet. 2012;8(4):e1002631. doi: 10.1371/journal.pgen.1002631. Epub 2012 Apr 5.
To gain insight into the molecular genetic basis of standing variation in fitness related traits, we identify a novel factor that regulates the molecular and physiological basis of natural variation in female Drosophila melanogaster fecundity. Genetic variation in female fecundity in flies derived from a wild orchard population is heritable and largely independent of other measured life history traits. We map a portion of this variation to a single QTL and then use deficiency mapping to further refine this QTL to 5 candidate genes. Ubiquitous expression of RNAi against only one of these genes, an aquaporin encoded by Drip, reduces fecundity. Within our mapping population Drip mRNA level in the head, but not other tissues, is positively correlated with fecundity. We localize Drip expression to a small population of corazonin producing neurons located in the dorsolateral posterior compartments of the protocerebrum. Expression of Drip-RNAi using both the pan-neuronal ELAV-Gal4 and the Crz-Gal4 drivers reduces fecundity. Low-fecundity RILs have decreased Crz expression and increased expression of pale, the enzyme encoding the rate-limiting step in the production of dopamine, a modulator of insect life histories. Taken together these data suggest that natural variation in Drip expression in the corazonin producing neurons contributes to standing variation in fitness by altering the concentration of two neurohormones.
为了深入了解与适应相关特征的立位变异的分子遗传基础，我们鉴定出一种新的调节因子，它调节了自然变异的分子和生理基础在雌性黑腹果蝇生殖力中。源于野生果园种群的雌性生殖力的遗传变异是可遗传的，并且在很大程度上独立于其他测量的生活史特征。我们将此部分变异映射到一个单一的 QTL 上，然后使用缺失作图将此 QTL 进一步精确定位到 5 个候选基因。针对这些基因中的一个基因（由 Drip 编码的水通道蛋白）的 RNAi 的普遍表达降低了生殖力。在我们的作图群体中，Drip mRNA 水平在头部，而不是其他组织，与生殖力呈正相关。我们将 Drip 表达定位到位于原脑背外侧后区的一小群产生 corazonin 的神经元中。使用 pan-neuronal ELAV-Gal4 和 Crz-Gal4 驱动子表达 Drip-RNAi 会降低生殖力。低生殖力 RILs 具有降低的 Crz 表达和增加的 pale 表达，pale 编码多巴胺产生的限速步骤的酶，多巴胺是昆虫生活史的调节剂。综上所述，这些数据表明，corazonin 产生神经元中 Drip 表达的自然变异通过改变两种神经激素的浓度来导致适应相关特征的立位变异。
