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Updated: Jul 25, 2026

Microinjection for Transgenesis and Genome Editing in Threespine Sticklebacks
Published on: May 13, 2016
Complex evolution of vitellogenin genes in salmonid fishes
N Buisine1, V Trichet, J Wolff
1Université de Bretagne Sud, Campus de Tohannic, BP 573, 56017 Vannes, France. nicolas.buisine@bioch.ox.ac.uk
Abstract:
Vitellogenins (Vtg) are usually encoded by small multigene families containing up to six genes. With 20 tandemly arranged genes, the rainbow trout ( Oncorhynchus mykiss) is an exception to this rule. PCR amplification, cloning and sequence analysis of Vtg genes in other salmonid species revealed the existence of two paralogous gene clusters, designated Vtg-A and Vtg-B. Southern hybridization showed that the number of genes varies from 2 to 30 copies from one species to another, as well as between the two gene clusters. All Coregonus, Thymallus, Salmo and Salvelinus species studied have both gene clusters, while Oncorhynchus species possess only the Vtg-A locus. Phylogenetic trees constructed from Vtg sequences revealed conflicting nodes with the consensus tree based on morphological and anatomical data. Vtg sequences support the grouping ( Salmo, ( Salvelinus, Oncorhynchus)) instead of the accepted consensus ( Salvelinus, ( Salmo, Oncorhynchus)). Structural data on gene organization also support the contention that Salvelinus and Oncorhynchus are sister taxa. Evolutionary implications for the Vtg gene clusters in salmonids are discussed.
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The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
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