Extensive lineage-specific gene duplication and evolution of the spiggin multi-gene family in sticklebackReport as inadecuate




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BMC Evolutionary Biology

, 7:209

First Online: 04 November 2007Received: 05 June 2007Accepted: 04 November 2007

Abstract

BackgroundThe threespine stickleback Gasterosteus aculeatus has a characteristic reproductive mode; mature males build nests using a secreted glue-like protein called spiggin. Although recent studies reported multiple occurrences of genes that encode this glue-like protein spiggin in threespine and ninespine sticklebacks, it is still unclear how many genes compose the spiggin multi-gene family.

ResultsGenome sequence analysis of threespine stickleback showed that there are at least five spiggin genes and two pseudogenes, whereas a single spiggin homolog occurs in the genomes of other fishes. Comparative genome sequence analysis demonstrated that Muc19, a single-copy mucous gene in human and mouse, is an ortholog of spiggin. Phylogenetic and molecular evolutionary analyses of these sequences suggested that an ancestral spiggin gene originated from a member of the mucin gene family as a single gene in the common ancestor of teleosts, and gene duplications of spiggin have occurred in the stickleback lineage. There was inter-population variation in the copy number of spiggin genes and positive selection on some codons, indicating that additional gene duplication-deletion events and adaptive evolution at some amino acid sites may have occurred in each stickleback population.

ConclusionA number of spiggin genes exist in the threespine stickleback genome. Our results provide insight into the origin and dynamic evolutionary process of the spiggin multi-gene family in the threespine stickleback lineage. The dramatic evolution of genes for mucous substrates may have contributed to the generation of distinct characteristics such as -bio-glue- in vertebrates.

List of AbbreviationsCopy number variationCNV

Linkage groupLG

Open reading frameORF

Von Willebrand factor D-domainVWD

Neighbor-joiningNJ

Maximum-likelihoodML

Posterior probabilityPP

Glyceraldehyde-3-phosphate dehydrogenaseGAPDH

Likelihood-ratio testLRT

Bayes empirical BayesBEB.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2148-7-209 contains supplementary material, which is available to authorized users.

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Author: Ryouka Kawahara - Mutsumi Nishida

Source: https://link.springer.com/article/10.1186/1471-2148-7-209



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