Meeting Abstract

33.3  Friday, Jan. 4  Fresh Insights from RNA-Seq Analysis into Black Widow Spider Venom Composition and Evolution GARB, J.E.*; HAYASHI, C.Y.; LANCASTER, A.K.; CORBETT, S.; AYOUB , N.A.; University of Massachusetts Lowell; University of California, Riverside; Whitehead Institute for Biomedical Research; University of Massachusetts Lowell; Washington and Lee University Jessica_Garb@uml.edu

Venoms are chemically complex secretions that have independently evolved in several animal lineages for the purposes of predation and defense. Venoms have attracted enormous interest because of their pharmacological applications, and because of their dynamic evolutionary histories, which can be directly linked to organismal ecology. Despite the biological importance of venoms, their molecular composition and evolution is poorly understood in many medically significant and ecologically interesting species. A case in point are the black widow spiders, representing several species in the genus Latrodectus, which have a potent neurotoxic venom that immobilizes both vertebrate and invertebrate prey. We assembled venom gland gene transcripts from the Western black widow spider (Latrodectus hesperus) using Illumina RNA-Seq libraries as well as traditional cDNA libraries. We compared these venom transcripts to Illumina-derived transcripts from L. hesperus silk gland and cephalothorax tissues. Our analyses identified large numbers of transcripts that are exclusively or primarily expressed in venom glands, including many novel toxin sequences. Our results show that black widow venom has far greater molecular complexity than previously realized, which is in part explained by dramatic expansion of toxin gene families. We are expanding this transcriptomic work across related species to further understand how changes in molecular composition and gene expression have led to the extreme toxicity of black widow venom.