Nymphalid T1 leg expression - Hoile et al

This study analysed the evolution of gene expression in the reduced first thoracic (T1) legs of nymphalid butterflies. Species in the family Nymphalidae have greatly reduced forelegs in both male and females, which have lost their walking functions and are thought to play a role in sensory behaviours including oviposition. To assess whether changes in gene expression correlate with this phenotype we sampled Maniola jurtina (meadow brown butterfly) for RNA sequencing to carry out differential gene expression analyses between T1 legs and the remaining legs, as well as between T1 legs and palps. While all legs share similar expression profiles, we find T1 legs have an expression profile distinct from the other legs and the palps. We do find over 250 genes which show similar expression profiles in T1 legs and palps, when compared to the other legs. These genes primarily consist of those with metabolic functions, including a trypsin-domain protein which underwent large gene expansion specifically within the nymphalid butterflies. We also find shared (T1 legs and palps) and distinct (T1 or palps) chemosensory gene expression suggesting an increased sensory role in the T1 legs compared to the other legs. All data and code used in this study are available on this figshare repository. If there are any queries about any of the files please do not hesitate to contact any of the authors.