Super Spider Gene Sequence Discovered

Scientistshave uncovered the genetic sequence for one of the strongest silks that spidersproduce, a discovery that could one day be used to make super spider-silkproducts for humans.

Not all spidersilk are created equal. For example, spiders use dragline silk to create thescaffolding for their webs, but another type of silk, known as capture silk, isused to fill out the web. While dragline silk is strong, capture silk is moreelastic and also sticky, making it better suited for trapping insects thatstray too close.

In total, spiders produce approximately seven different types of silk,which they make using special silkglands. The silk threads are spooled out of the external parts of theglands, known as spinnerets. Spiders often have numerous pairs of spinnerets,which they use to produce different types of silk.

Inaddition to catching and storing food, spiders also use silk for movement andfor reproduction.

One of thestrongest and most durable types of spider silk is produced only by sexuallymature females and is used to construct protective cocoons for their eggs.

"Theprotein of the egg-case fibers has a different function altogether from that ofthe other silks," said Jessica Garb, a postdoctoral researcher and a co-authoron the study.

"Egg-casesilk has to last a long time and therefore must be durable under a widevariety of conditions, from freezing to very high temperatures. It needs to bestrong enough to protect the eggs from threats such as predators, parasites andmolds," Garb said.

Theseproperties could also make it ideally suited for human purposes.

"Collectively,spider silks are some of the toughest natural fibers known," said CherylHayashi, an assistant biology professor at the University of California,Riverside. "Imagine a fabric made fromsuch a substance? It would be incredibly strong, flexible and ultimately,biodegradable."

In additionto body armor, researchersare also working to develop spider-silk rope and spider-silk micro-sutures foruse in surgery.

Using molecular biology labtechniques, Hayashi and Garb uncovered the sequence of molecules called aminoacids for a major protein component in egg case silk known as Tusp1. Theirfinding is important because mechanical properties like the strength,elasticity and durability of a silk is determined by its amino acid sequence,and scientists have been successful in discovering only a handful of suchsequences.

Theresearcher’s findings are detailed in the August 1 issue of the journal for theProceedings of the National Academy of Sciences.