Drosophila simulans strain:Nueva Phenotype or Genotype

The goal of our project was to identify the genetic basis for ecological specialization. The fruit fly Drosophila sechellia is a specialist that utilizes a single resource, the fruit of Morinda citrifolia, which is toxic to other species of the melanogaster subgroup when it is ripe. Crosses between D. sechellia and its sibling species,D. simulans produce fertile female offspring, allows a genetic approach. We use multiplexed shotgun genotyping and high resolution QTL analysis to examine the genetic basis of resistance to M. citrifolia fruit toxin. We find that at least four dominant and four recessive loci interact additively to confer resistance to the M. citrifolia fruit toxin. We identify a dominant locus of large effect on the third chromosome (QTL-IIIsima) that was not detected in previous analyses. The identification of QTL-IIIsima, here, is an important step towards identifying the molecular basis of specialization upon M. citrifolia fruit by D. sechellia.

本研究旨在解析生态特化的遗传基础。塞氏果蝇（Drosophila sechellia）是一种特化物种，仅利用单一宿主资源——海巴戟（Morinda citrifolia）的果实；该果实成熟后对黑腹果蝇组（melanogaster subgroup）的其他物种具有毒性。将塞氏果蝇与其近缘物种拟果蝇（Drosophila simulans）进行杂交，可获得可育雌性后代，为开展遗传学研究提供了可行路径。本研究采用多重鸟枪基因分型（multiplexed shotgun genotyping）与高分辨率数量性状位点（QTL）分析技术，探究塞氏果蝇对海巴戟果实毒素的抗性遗传基础。研究发现，至少4个显性位点与4个隐性位点通过加性互作，赋予塞氏果蝇对海巴戟果实毒素的抗性。我们在3号染色体上定位到一个效应显著的显性位点（QTL-IIIsima），该位点在既往研究中未被检出。本次QTL-IIIsima的定位，为解析塞氏果蝇对海巴戟果实产生生态特化的分子机制迈出了重要一步。