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ON WEIGHTING AND CONGRUENCE.

Marc W Allard1, James M Carpenter2

  • 1Department of Biological Sciences, The George Washington University, Washington, DC, 20052, U.S.A.

Cladistics : the International Journal of the Willi Hennig Society
|December 18, 2021
PubMed
Summary
This summary is machine-generated.

A priori differential weighting in molecular phylogenetics can improve data congruence. Weighting transversions enhanced congruence among mitochondrial genes, though the resulting phylogenetic tree was similar to one with equally weighted data.

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Area of Science:

  • Evolutionary biology
  • Molecular phylogenetics
  • Bioinformatics

Background:

  • A priori differential weighting of molecular characters is a common but subjective practice in phylogenetics.
  • This method aims to reduce data set heterogeneity and improve congruence using conservative characters.
  • Lack of clear criteria for weighting can impact phylogenetic accuracy.

Purpose of the Study:

  • To investigate whether a priori differential weighting improves data congruence in molecular phylogenetics.
  • To evaluate the effectiveness of specific weighting strategies, such as omitting third codon positions and weighting transversions.
  • To assess the impact of weighting on the resulting phylogenetic trees.

Main Methods:

  • Utilized the incongruence length difference (ILD) test to assess congruence.
  • Applied a priori differential weighting to a linked genetic data set.
  • Analyzed 14 mammalian taxa and 13 protein-coding genes from the mitochondrial genome.
  • Compared results from equally weighted data, data with omitted third codon positions, and data weighted by transversions.

Main Results:

  • Omitting the third codon position did not improve congruence compared to equally weighted data.
  • Weighting transversions significantly improved congruence among the 13 protein-coding genes.
  • The most parsimonious tree derived from transversion weighting was identical to the tree from equally weighted data.

Conclusions:

  • A priori differential weighting, specifically transversion weighting, can enhance congruence in molecular data sets.
  • While congruence improves, the overall phylogenetic signal may not necessitate differential weighting for tree topology.
  • Further research is needed to establish objective criteria for differential weighting in phylogenetic analyses.