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Methodological aspects of molecular phylogeny of fishes

By Cyril - Posted on 17 April 2014

TitleMethodological aspects of molecular phylogeny of fishes
Publication TypeMiscellaneous
Year of Publication1996
AuthorsLecointre G
AbstractFish phylogeny has seen 2 major methodological changes during the last 30 years. First, the introduction of cladistics in Ichthyology in the late 1960s led to dramatic progress in fish classification and phylogeny. Second, molecular methods and especially DNA sequence data offered new collections of discrete characters useful for phylogenetic investigations, especially for phylogenetic problems left unresolved by morphological characters. But until now, their impact on fish phylogeny has remained limited. Whatever the aim of a study, fundamental or applied, different kinds of molecular methods exist, among which those allowing identification of molecular structures (such as sequencing) should be preferred, in order to avoid ''experimental screens'' which are described herein. The choice of genes, species, and tree-construction methods presents pitfalls that one should avoid. Robustness of phylogenetic trees should be considered. Differences exist between molecularists (geneticists) and morphologists as to their respective conceptions of phylogenetic trees. Distance-matrix methods are widely used in the Ist group, and a naive essentialist way to consider sequence alignment and trees is often encountered. Cladistics was born in the world of morphologists, Most molecularists have not yet reached the corresponding ''phylogenetic maturity''. Only parsimony methods allow researchers to identify in fine homologuous characters, and are, therefore, really phylogenetic. A phylogeny, as an inference on the history of life, must be performed with hypotheticodeductive methods. Parsimony methods should therefore be preferred over distance-matrix methods.