Welcome to the American Ornithological Society 2018 Annual Conference. We are pleased to have you join us at the lovely Hilton El Conquistador Resort in Tucson, AZ.
Manakins are neotropical suboscines with acrobatic sexual displays performed using the fastest known vertebrate limb muscles. The Scapulohumeralis caudalis (SH) muscle is responsible for medial movement of the humerus and is integral for manakin displays with complex wing movements. Previous studies have revealed elevated androgen receptor (AR) expression in the SH muscle of species with complex wing displays. In this study we used RNA-seq to characterize in detail the regulatory changes associated with the evolution of complex wing displays in manakins. We obtained transcript expression levels derived from the SH and Pectoralis (PEC) muscles from six manakin species and a flycatcher (Tyrannidae). We compared expression levels of 7,194 transcripts between species with and without rapid wing movements, and found differential expression associated with skeletal muscle contraction, muscle filament sliding, and actin-mediated cell contraction gene ontology (GO) categories. Our analyses confirm the up-regulation of AR but also reveal differential expression of AR-associated heat shock proteins and downstream transcription factors. Ongoing analyses will examine rates and patterns of molecular evolution and test for signatures of positive selection on these genes.
