HAYASHI, C.Y.: Convergent Evolution of Sequence Elements in Spider and Insect Silk Proteins

Silks spun from the abdominal glands of spiders and silks drawn from the labial glands of insects are considered to be independently evolved proteins. Surprisingly, the amino acid sequences of some spider silks are much more similar to the sequences of moth silks than to other spider silks. For example, translated cDNA sequences from a jumping spider fibroin are almost indistinguishable from the heavy-chain fibroin of the domesticated silkworm. Such similarities in the proteins from a spider and a moth reflect convergence at a fine-scale molecular level. By comparing members of independently evolved silk protein families from a variety of spiders and insects, sequence elements that are critical to the formation and/or performance of silk fibers may be identified.