title: Venom Insulins of Cone Snails Diversify Rapidly and Track Prey Taxa.
abstract: A specialized insulin was recently found in the venom of a fish-hunting cone snail, Conus geographus Here we show that many worm-hunting and snail-hunting cones also express venom insulins, and that this novel gene family has diversified explosively. Cone snails express a highly conserved insulin in their nerve ring; presumably this conventional signaling insulin is finely tuned to the Conus insulin receptor, which also evolves very slowly. By contrast, the venom insulins diverge rapidly, apparently in response to biotic interactions with prey and also possibly the cones' own predators and competitors. Thus, the inwardly directed signaling insulins appear to experience predominantly purifying sele\ction to target an internal receptor that seldom changes, while the outwardly directed venom insulins frequently experience directional selection to target heterospecific insulin receptors in a changing mix of prey, predators and competitors. Prey insulin receptors may often be constrained in ways that prevent their evolutionary escape from targeted venom insulins, if amino-acid substitutions that result in escape also degrade the receptor's signaling functions.
authors.affiliation: Department of Biology, University of Utah, Salt Lake City, UT Department of Biology, University of Copenhagen, Copenhagen, Denmark helena.safavi@utah.edu.
authors.forename: Helena
authors.initials: H
authors.lastname: Safavi-Hemami
authors.affiliation: School of Life Sciences and Technology, Institute of Protein Research, Tongji University, Shanghai, China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Lu
authors.affiliation: Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT.
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.affiliation: A.N. Severtzov Institute of Ecology and Evolution, Russian Academy of Science, Leninsky Prospect, Moscow, Russia.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Fedosov
authors.affiliation: University of Guam Marine Laboratory, Agana, Guam.
authors.forename: Jason
authors.initials: J
authors.lastname: Biggs
authors.affiliation: Department of Biology, University of Utah, Salt Lake City, UT.
authors.forename: Patrice
authors.initials: P
authors.lastname: Showers Corneli
authors.affiliation: Department of Biology, University of Utah, Salt Lake City, UT.
authors.forename: Jon
authors.initials: J
authors.lastname: Seger
authors.affiliation: Eccles Institute of Human Genetics, University of Utah, Salt Lake City, UT USTAR Center for Genetic Discovery, University of Utah, Salt Lake City, UT.
authors.forename: Mark
authors.initials: M
authors.lastname: Yandell
authors.affiliation: Department of Biology, University of Utah, Salt Lake City, UT.
authors.forename: Baldomero M
authors.initials: BM
authors.lastname: Olivera
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001499:Bayes Theorem; D020916:Conotoxins / Q000096:biosynthesis / Q000235:genetics* / Q000633:toxicity; D052078:Conus Snail / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D014644:Genetic Variation; D007328:Insulin / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D011972:Receptor, Insulin / Q000235:genetics / Q000378:metabolism; D014688:Venoms / Q000096:biosynthesis / Q000235:genetics
chemical_list: D020916:Conotoxins; D007328:Insulin; D014688:Venoms; D011972:Receptor, Insulin
keywords: diversification; insulin gene family; venom