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On the independent gene trees assumption in phylogenomic studies
Author(s) -
Jennings W. Bryan
Publication year - 2017
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/mec.14274
Subject(s) - coalescent theory , biology , evolutionary biology , population , effective population size , genetics , population genetics , bayes' theorem , mendelian inheritance , phylogenetic tree , gene , bayesian probability , statistics , mathematics , genetic variation , demography , sociology
Multilocus coalescent methods for inferring species trees or historical demographic parameters typically require the assumption that gene trees for sampled SNP s or DNA sequence loci are conditionally independent given their species tree. In practice, researchers have used different criteria to delimit “independent loci.” One criterion identifies sampled loci as being independent of each other if they undergo Mendelian independent assortment ( IA criterion). O'Neill et al. (2013, Molecular Ecology , 22, 111–129) used this approach in their phylogeographic study of North American tiger salamander species complex. In two other studies, researchers developed a pair of related methods that employ an independent genealogies criterion ( IG criterion), which considers the effects of population‐level recombination on correlations between the gene trees of intrachromosomal loci. Here, I explain these three methods, illustrate their use with example data, and evaluate their efficacies. I show that the IA approach is more conservative, is simpler to use and requires fewer assumptions than the IG approaches. However, IG approaches can identify much larger numbers of independent loci than the IA method, which, in turn, allows researchers to obtain more precise and accurate estimates of species trees and historical demographic parameters. A disadvantage of the IG methods is that they require an estimate of the population recombination rate. Despite their drawbacks, IA and IG approaches provide molecular ecologists with promising a priori methods for selecting SNP s or DNA sequence loci that likely meet the independence assumption in coalescent‐based phylogenomic studies.