Inference of Horizontal Genetic Transfer from Molecular Data: An Approach Using the Bootstrap

AUTOR(ES)
RESUMO

Inconsistencies in taxonomic relationships implicit in different sets ofnucleic acid sequences potentially result from horizontal transfer ofgenetic material between genomes. A nonparametric method is proposed todetermine whether such inconsistencies are statistically significant. Asimilarity coefficient is calculated from ranked pairwise identities andevaluated against a distribution of similarity coefficients generatedfrom resampled data. Subsequent analyses of partial data sets, obtainedby the elimination of individual taxa, identify particular taxa to whichthe significance may be attributed, and can sometimes help indistinguishing horizontal genetic transfer from inconsistencies due toconvergent evolution or variation in evolutionary rate. The method wassuccessfully applied to data sets that were not found to be significantlydifferent with existing methods that use comparisons of phylogenetictrees. The new statistical framework is also applicable to the inferenceof horizontal transfer from restriction fragment length polymorphismdistributions and proteinsequences.

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