Data from: Genetic architecture underlying morning and evening circadian phenotypes in fruit flies Drosophila melanogaster

Circadian rhythms are perhaps among the genetically best characterised behaviours. Several mutations with drastic effects on circadian processes have been identified and models developed to explain how clock genes and their products generate self-sustained oscillations. While natural variations in circadian phenotypes have been studied extensively, the genetic basis of such adaptive variations remains largely unknown. Here we report the results of a preliminary genetic analysis of adaptive divergence of circadian phenotypes in populations of fruit flies Drosophila melanogaster. Two sets of populations- early and late were created in a long-term laboratory selection for morning and evening emergence with four independent replicates each. Over the course of ~55 generations, the early flies evolved increased morning emergence and shorter circadian period, while late flies evolved increased evening emergence and longer period. To examine the genetic basis of circadian phenotypes, we set-up crosses between early and late flies and monitored emergence and activity/rest rhythms in the F1, backcrossed and F2 progeny. Our analysis suggests that the genetic basis of divergent circadian phenotypes in early and late stocks is primarily autosomal. Line-cross analysis revealed that additive and non-additive genetic effects contribute to the divergence of circadian phenotypes in early and late flies.昼夜节律（circadian rhythms）或许是遗传学层面研究最为透彻的行为性状之一。学界已鉴定出多种对昼夜节律过程具有显著影响的突变，并构建了相关模型以阐释生物钟基因及其产物如何产生自持振荡。尽管学界已对昼夜节律表型的自然变异开展了大量研究，但这类适应性变异的遗传基础仍在很大程度上尚不明确。本研究针对黑腹果蝇（Drosophila melanogaster）种群中昼夜节律表型的适应性分化开展了初步遗传分析，现将结果报道如下：研究通过长期实验室选择实验，构建了两组果蝇种群——早型组与晚型组，分别对应早晨羽化与傍晚羽化表型，每组均设置4个独立重复。经过约55个世代的选育，早型组果蝇的早晨羽化比例显著提升，昼夜节律周期缩短；晚型组果蝇的傍晚羽化比例则显著升高，昼夜节律周期延长。为探究昼夜节律表型的遗传基础，本研究将早型组与晚型组果蝇进行杂交，并对F1、回交及F2后代的羽化行为与活动-休息节律进行了监测。本研究分析结果表明，早、晚型选育种群间昼夜节律表型分化的遗传基础主要位于常染色体上；系谱杂交分析显示，加性遗传效应与非加性遗传效应共同参与了早、晚型果蝇昼夜节律表型的分化过程。