Abstract
Vascular patterning is a key, genetically responsive phylogenetic classifier of tissues in major organisms flown in space, such as the wings of Drosophila melanogaster (the fruit fly), mouse retina, and leaves of Arabidopsis thaliana. Phenotypes of increasingly abnormal ectopic wing venation in the highly stereotyped Drosophila wing generated by overexpressing the H-C2 construct of Notch antagonist Hairless (Johannes and Preiss, 2002) were mapped and quantified by NASA’s VESsel GENeration Analysis (VESGEN) software. By several confirming vascular parameters, the eight stereotyped wing veins remained quite constant in wild type compared to Class 5 H-C2, the most perturbed category of the H-C2 overexpression phenotypes. However, ectopic veins increased in number from 1 in the wild type, to 18 in Class 5 H-C2. We therefore demonstrate the feasibility of using VESGEN to quantify microscopic images of altered wing venation in Drosophila melanogaster. We further determined that several of the signal transduction pathways affecting wing vein patterning were altered by spaceflight, according to gene expression differences observed in our transcriptomic data from a previous shuttle flight experiment. Future studies will help characterize the extent to which these gene expression changes can cause even subtle developmental changes using model organisms, such as Drosophila. Therefore, we propose that the sensitive analyses provided by VESGEN software will not only serve as a useful tool to map the genetics of wing vein patterning for terrestrial applications, but also for future phenotypic studies with Drosophila for spaceflight missions.