Javier García-Cruz

Coding Quantitative Character Data for Phylogenetic Analysis: A Comparison of Five Methods

Abstract Five character construction methods were compared for a data set of 25 quantitative morphological characters sampled from the Govenia superba complex. The methods were simple-gap, gap coding, gap-weighting, analysis of variance followed by a multiple range test, and an “arbitrary” coding method. Three indices, data decisiveness, consistency index, and skewness (g1), were used as estimators of phylogenetic signal. Performance of coding methods was evaluated by the following criteria: (1) number of informative characters, (2) number of equally parsimonious trees, (3) clade support measured by bootstrapping, and (4) phylogenetic signal, compared using randomization tests that established critical values for the three indices and allowed them to be compared between coding methods. This study demonstrates that a large number of characters are accessible for phylogenetic analysis when continuous characters are included. The quantitative character data for the Govenia complex contain significant phylogenetic information when the gap-weighting method is used to construct character states. This indicates that methods that divide variation into small segments and allow overlapping of measurements recover a strong phylogenetic signal, and yield small number of well-resolved trees with strong bootstrap support and statistically significant phylogenetic signal. In contrast, methods such as gap coding or analysis of variance-multiple range test lead to data matrices with few informative characters and many equally parsimonious trees and weak phylogenetic signal. Moreover, the simple-gap coding method data matrix failed to recover significant phylogenetic signal.

Genetic Diversity in Six Govenia (Orchidaceae) Species with Different Pollinator Attraction Strategies

A few generalizations have been made about the amount of genetic diversity and life‐history traits in plants, and a number of studies have reported contrasting results, indicating that these generalizations are not necessarily reliable. Six Govenia species belonging to three groups characterized by different pollinator attraction strategies were studied: (a) small inflorescences with three to eight whitish or greenish flowers, (b) medium‐sized inflorescences with 15–30 white flowers, and (c) large inflorescences with 30–50 or more yellowish flowers. Genetic variation was assessed using starch gel electrophoresis to resolve 17 allozyme loci in 13 populations, to determine the level and distribution of genetic variation, and to evaluate the association between genetic diversity and pollinator attraction strategy. A high level of genetic variation and a low genetic differentiation among species were found. The mean number of alleles per locus was higher among species with strategy c than species with strategy a ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

A new species of Govenia (Orchidaceae) from Chiapas, Mexico

A=2.23

NOTAS SOBRE EL GÉNERO HABENARIA (ORCHIDACEAE) EN MÉXICO

\end{document} vs. 2.0), and the genetic diversity within populations was higher among taxa with strategy a than with strategy c ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

Relaciones fi logenéticas de la subtribu Oncidiinae (Orchidaceae) inferidas a partir de caracteres estructurales y secuencias de ADN (ITS y matK): un enfoque combinado Phylogenetic relationships of the subtribe Oncidiinae (Orchidaceae) inferred from structural and DNA sequences (matK, ITS): a combined approach

H_{\mathrm{o}\,}=0.72

Vascular epiphytes in the state of Hidalgo, Mexico: diversity and distribution.

\end{document} vs. 0.46), while population differentiation was lower for strategy a than for strategy c ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape