Tags

Type your tag names separated by a space and hit enter

Early events in the evolution of spider silk genes.
PLoS One 2012; 7(6):e38084Plos

Abstract

Silk spinning is essential to spider ecology and has had a key role in the expansive diversification of spiders. Silk is composed primarily of proteins called spidroins, which are encoded by a multi-gene family. Spidroins have been studied extensively in the derived clade, Orbiculariae (orb-weavers), from the suborder Araneomorphae ('true spiders'). Orbicularians produce a suite of different silks, and underlying this repertoire is a history of duplication and spidroin gene divergence. A second class of silk proteins, Egg Case Proteins (ECPs), is known only from the orbicularian species, Lactrodectus hesperus (Western black widow). In L. hesperus, ECPs bond with tubuliform spidroins to form egg case silk fibers. Because most of the phylogenetic diversity of spiders has not been sampled for their silk genes, there is limited understanding of spidroin gene family history and the prevalence of ECPs. Silk genes have not been reported from the suborder Mesothelae (segmented spiders), which diverged from all other spiders >380 million years ago, and sampling from Mygalomorphae (tarantulas, trapdoor spiders) and basal araneomorph lineages is sparse. In comparison to orbicularians, mesotheles and mygalomorphs have a simpler silk biology and thus are hypothesized to have less diversity of silk genes. Here, we present cDNAs synthesized from the silk glands of six mygalomorph species, a mesothele, and a non-orbicularian araneomorph, and uncover a surprisingly rich silk gene diversity. In particular, we find ECP homologs in the mesothele, suggesting that ECPs were present in the common ancestor of extant spiders, and originally were not specialized to complex with tubuliform spidroins. Furthermore, gene-tree/species-tree reconciliation analysis reveals that numerous spidroin gene duplications occurred after the split between Mesothelae and Opisthothelae (Mygalomorphae plus Araneomorphae). We use the spidroin gene tree to reconstruct the evolution of amino acid compositions of spidroins that perform different ecological functions.

Authors+Show Affiliations

Department of Biology, University of California Riverside, Riverside, California, United States of America.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

22761664

Citation

Starrett, James, et al. "Early Events in the Evolution of Spider Silk Genes." PloS One, vol. 7, no. 6, 2012, pp. e38084.
Starrett J, Garb JE, Kuelbs A, et al. Early events in the evolution of spider silk genes. PLoS ONE. 2012;7(6):e38084.
Starrett, J., Garb, J. E., Kuelbs, A., Azubuike, U. O., & Hayashi, C. Y. (2012). Early events in the evolution of spider silk genes. PloS One, 7(6), pp. e38084. doi:10.1371/journal.pone.0038084.
Starrett J, et al. Early Events in the Evolution of Spider Silk Genes. PLoS ONE. 2012;7(6):e38084. PubMed PMID: 22761664.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Early events in the evolution of spider silk genes. AU - Starrett,James, AU - Garb,Jessica E, AU - Kuelbs,Amanda, AU - Azubuike,Ugochi O, AU - Hayashi,Cheryl Y, Y1 - 2012/06/22/ PY - 2012/03/02/received PY - 2012/05/02/accepted PY - 2012/7/5/entrez PY - 2012/7/5/pubmed PY - 2013/3/27/medline SP - e38084 EP - e38084 JF - PloS one JO - PLoS ONE VL - 7 IS - 6 N2 - Silk spinning is essential to spider ecology and has had a key role in the expansive diversification of spiders. Silk is composed primarily of proteins called spidroins, which are encoded by a multi-gene family. Spidroins have been studied extensively in the derived clade, Orbiculariae (orb-weavers), from the suborder Araneomorphae ('true spiders'). Orbicularians produce a suite of different silks, and underlying this repertoire is a history of duplication and spidroin gene divergence. A second class of silk proteins, Egg Case Proteins (ECPs), is known only from the orbicularian species, Lactrodectus hesperus (Western black widow). In L. hesperus, ECPs bond with tubuliform spidroins to form egg case silk fibers. Because most of the phylogenetic diversity of spiders has not been sampled for their silk genes, there is limited understanding of spidroin gene family history and the prevalence of ECPs. Silk genes have not been reported from the suborder Mesothelae (segmented spiders), which diverged from all other spiders >380 million years ago, and sampling from Mygalomorphae (tarantulas, trapdoor spiders) and basal araneomorph lineages is sparse. In comparison to orbicularians, mesotheles and mygalomorphs have a simpler silk biology and thus are hypothesized to have less diversity of silk genes. Here, we present cDNAs synthesized from the silk glands of six mygalomorph species, a mesothele, and a non-orbicularian araneomorph, and uncover a surprisingly rich silk gene diversity. In particular, we find ECP homologs in the mesothele, suggesting that ECPs were present in the common ancestor of extant spiders, and originally were not specialized to complex with tubuliform spidroins. Furthermore, gene-tree/species-tree reconciliation analysis reveals that numerous spidroin gene duplications occurred after the split between Mesothelae and Opisthothelae (Mygalomorphae plus Araneomorphae). We use the spidroin gene tree to reconstruct the evolution of amino acid compositions of spidroins that perform different ecological functions. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/22761664/Early_events_in_the_evolution_of_spider_silk_genes_ L2 - http://dx.plos.org/10.1371/journal.pone.0038084 DB - PRIME DP - Unbound Medicine ER -