Genetic Relationships AmongSalvelinusSpecies Inferred from Allozyme Data

Abstract

We studied phylogenetic relationships in the genus Salvelinus with emphasis on S. alpinus, S. malma, and S. confluentus. Sixty allozyme loci were resolved in 422 individuals representing six species from a worldwide distribution. We used phenetic (UPGMA), phylogenetic (Fitch and Margoliash), and maximum-likelihood techniques to derive estimates of Salvelinus phylogeny. Three almost identical topologies were produced, but we chose the Fitch and Margoliash topology as the best phylogenetic estimate. The distances used to construct this tree assume that gene frequencies are affected only by genetic drift, which we argued was the dominant speciation force in Salvelinus. This topology was also the shortest. Jackknifing the Fitch and Margoliash tree resolved the branching order among the three Salvelinus subgenera: S. [Baione], S. [Cristivomer], and S. [Salvelinus]. It also revealed two sister groups within the Salvelinus subgenus: S. leucomaenis – S. confluentus and S. alpinus – S. malma.