Silk Protein Evolution and Spider Phylogenetics: an EST Approach

University Of California-Riverside, Riverside CA

Investigators

Abstract

Dr. Cheryl Hayashi at the University of California, Riverside has received a grant to study the evolution of spiders and their silk proteins. The dragline silks of orb-weaving spiders are highly prized as biomaterials because these protein-based fibers have remarkable combinations of strength and toughness. Most knowledge of dragline silks comes from studies done on two species. With over 34,000 described species, and with most species spinning multiple types of silks in addition to the dragline, spider silks are incredibly diverse. Very little is actually known about the mechanical properties and genetics of spider silks. Dr. Hayashi's first goal is to document the extensive molecular and biomechanic variation of spider silks. To do this, she will perform tensile tests of silk fibers spun by different species of spiders, and will then clone the gene transcripts that are expressed in silk gland tissue. The second goal of her study is to trace how silk gene sequences have changed as spiders evolved. This work involves reconstructing the phylogenetic history of spiders from DNA sequences. To accomplish her research objectives, Dr. Hayashi will train a postdoctoral scientist and a graduate student. In addition, undergraduate students at the University of California, Riverside will participate through small, independent projects that are designed to be completed within one or two academic quarters. The results of Dr. Hayashi's studies will advance the state of knowledge of silk proteins and spider evolution, and will significantly enlarge the international database of spider DNA sequences. The work is also relevant to commercial technologies that are being developed to mass-produce artificial spider silk. Correlational data that link performance of silk fibers to specific silk gene sequences are critical for the design of novel biomaterials.