Work

Spider Transcriptomes Identify Ancient Large-Scale Gene Duplication Event Potentially Important in Silk Gland Evolution

Year: 2015

Type: article

Abstract: The evolution of specialized tissues with novel functions, such as the silk synthesizing glands in spiders, is likely an influential driver of adaptive success. Large-scale gene duplication events and subsequent paralog divergence are thought to be required for generating evolutionary novelty. Such an event has been proposed for spiders, but not tested. We de novo assembled transcriptomes from three cobweb weaving spider species. Based on phylogenetic analyses of gene families with representatives from each of the three species, we found numerous duplication events indicative of a whole genome or segmental duplication. We estimated the age of the gene duplications relative to several speciation events within spiders and arachnids and found that the duplications likely occurred after the divergence of scorpions (order Scorpionida) and spiders (order Araneae), but before the divergence of the spider suborders Mygalomorphae and Araneomorphae, near the evolutionary origin of spider silk glands. Transcripts that are expressed exclusively or primarily within black widow silk glands are more likely to have a paralog descended from the ancient duplication event and have elevated amino acid replacement rates compared with other transcripts. Thus, an ancient large-scale gene duplication event within the spider lineage was likely an important source of molecular novelty during the evolution of silk gland-specific expression. This duplication event may have provided genetic material for subsequent silk gland diversification in the true spiders (Araneomorphae).

Source: Genome Biology and Evolution

DOI: 10.1093/gbe/evv110

Authors: Thomas H. Clarke, Jessica E. Garb, Cheryl Y. Hayashi, Peter Arensburger, Nadia A. Ayoub

Institutions: Washington and Lee University, University of Massachusetts Lowell, University of California, Riverside, California State Polytechnic University

Language: English

Topic: Silk-based biomaterials and applications

Subfield: Biomaterials

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,850