OAKLEY, T/H; SWARTZ, B/A; University of California, Santa Barbara; University of Cambridge: Supermatrix phylogenetic analyses support parallel evolution of complex life history (anadromy) in Atlantic and Pacific Salmon

Complex traits are of particular interest to evolutionists because they require the contribution of many individual adaptations. Unless biases exist, such as developmental constraints or ecological determinism, complex traits are expected to evolve the same way only once or very rarely. The complex behavior of anadromy – where adults migrate up rivers from the sea to the specific site of their birth for spawning – is well known in Atlantic and Pacific salmon. We will present phylogenetic analyses that indicate anadramous Atlantic (Salmo) and Pacific (Oncorhynchus) salmon/trouts are more distantly related to each other than traditionally believed. From the literature, we compiled a �supermatrix� of phylogenetic data on salmonid fishes and outgroups that is comprised of over 80 taxa and more than 34,000 characters from 34 different genes, morphology, allozymes, karyotypes, repetitive genomic elements, and other characters. Although results from individual data partitions were often ambiguous, increasing the amount of characters analyzed in supermatrix phylogenetic analyses indicated with increasing confidence that Oncorhynchus and non-anadramous Salvelinus (e.g. char and lake trout) are sister taxa. Using phylogenetic trees from our supermatrix, ancestral state reconstruction methods support separate, parallel origins of anadromy in Atlantic and Pacific salmon. Given that genomic scale methodologies (e.g. microarrays) are available for salmonids, the result of multiple origins of anadromy will provide a valuable system to study the genetics of novelty and complexity.