Credit: Matjaz Kuntner, Slovenian Academy of Sciences and Arts
Researchers at the University of Pennsylvania have been undergoing the arduous task of sequencing the entire genome of the golden orb-weaver spider, and have finally completed it. The scientists at Perelman School of Medicine used short tandem repeats to identify 28 silk proteins that make up the orb-weaver's spider silk, including one variety that was created in the venom sack. In addition to the silk proteins, DNA sequences were found that are believed to code for strength, elasticity, and other key features of spider silk.
Spider silk contains repeats of amino acids, some of which are repeated over a hundred times, which make them easy to identify using STR. In contrast to these repeating sequences, there are non-repetitive terminal domains that are vital in the formation of fibers from silk proteins. The process of going from proteins to fibers takes place through a complicated series of events, which ultimately results in the proteins being spun through the spinning duct to form a bi-folded, tightly controlled structure. For more information on the formation and composition of spider silk, please refer to this article from the National Library of Medicine.