GARB, J.E.*; HAYASHI, C.Y.; University of California, Riverside; University of California, Riverside: Strong and sticky gene products: molecular evolution of spider silk genes.

Spiders are unique in their ability to spin multiple types of task-specific silks. Each type of spider silk is composed of exceptionally long, repetitive protein molecules (fibroins) that are synthesized in specialized silk glands. Several lines of evidence demonstrate that a large gene family encodes the different fibroins. To date, only a small fraction of the silk gene family has been characterized at the nucleotide level. Moreover, the silk genes sequenced thus far are sampled from a small number of species. In order to reconstruct the evolutionary history of the spider silk gene family, we are using a comparative approach to isolate novel silk gene sequences from a phylogenetically broad spectrum of spiders. Specifically, we have constructed and screened cDNA libraries for novel silk transcripts from diverse taxa, including Hypochilus and Uloborus. We have also sequenced ESTs from these cDNA libraries in order to develop nuclear markers from which we will generate a spider species-tree. Using the species-tree in conjunction with the silk-gene tree, we will shed light on the patterns of gene duplications, losses, and divergences in the spider silk gene family.