Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses

The use of quantitative morphometric information for phylogenetic inference has been an intensely debated topic for most of the history of phylogenetic systematics. Despite several drawbacks, the most common strategy to include this sort of data into phylogenetic studies is the use of ratios, that i...

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Autores principales: Mongiardino Koch, N., Soto, I.M., Ramírez, M.J.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_03003256_v44_n5_p463_MongiardinoKoch
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spelling todo:paper_03003256_v44_n5_p463_MongiardinoKoch2023-10-03T15:17:33Z Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses Mongiardino Koch, N. Soto, I.M. Ramírez, M.J. The use of quantitative morphometric information for phylogenetic inference has been an intensely debated topic for most of the history of phylogenetic systematics. Despite several drawbacks, the most common strategy to include this sort of data into phylogenetic studies is the use of ratios, that is quotients between morphometric variables. Here, we discuss one particular problem associated with such methodology: the fact that the often arbitrary election of which variable serves as numerator and which as denominator affects the phylogenetic outcome of the analysis. We describe the cause for such an effect, and study its implications with the use of several published data matrices. Alternative coding schemes for ratio characters result in very different phylogenetic hypotheses, an effect that may even be strong enough to affect studies that combine continuous and discrete morphological information. Some of the resulting incongruence is produced by the differences in magnitude of the continuous characters involved, although different rescaling techniques are shown to decrease, but not eliminate, the confounding effect. To eliminate such problematic effect, ratios should be either log-transformed before their use or replaced by more effective ways to capture morphometric information. © 2015 Royal Swedish Academy of Sciences. Fil:Soto, I.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ramírez, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_03003256_v44_n5_p463_MongiardinoKoch
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description The use of quantitative morphometric information for phylogenetic inference has been an intensely debated topic for most of the history of phylogenetic systematics. Despite several drawbacks, the most common strategy to include this sort of data into phylogenetic studies is the use of ratios, that is quotients between morphometric variables. Here, we discuss one particular problem associated with such methodology: the fact that the often arbitrary election of which variable serves as numerator and which as denominator affects the phylogenetic outcome of the analysis. We describe the cause for such an effect, and study its implications with the use of several published data matrices. Alternative coding schemes for ratio characters result in very different phylogenetic hypotheses, an effect that may even be strong enough to affect studies that combine continuous and discrete morphological information. Some of the resulting incongruence is produced by the differences in magnitude of the continuous characters involved, although different rescaling techniques are shown to decrease, but not eliminate, the confounding effect. To eliminate such problematic effect, ratios should be either log-transformed before their use or replaced by more effective ways to capture morphometric information. © 2015 Royal Swedish Academy of Sciences.
format JOUR
author Mongiardino Koch, N.
Soto, I.M.
Ramírez, M.J.
spellingShingle Mongiardino Koch, N.
Soto, I.M.
Ramírez, M.J.
Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
author_facet Mongiardino Koch, N.
Soto, I.M.
Ramírez, M.J.
author_sort Mongiardino Koch, N.
title Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
title_short Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
title_full Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
title_fullStr Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
title_full_unstemmed Overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
title_sort overcoming problems with the use of ratios as continuous characters for phylogenetic analyses
url http://hdl.handle.net/20.500.12110/paper_03003256_v44_n5_p463_MongiardinoKoch
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