Congruence of chloroplast DNA restriction site characters with morphological and isozyme data in Solanum sect. Lasiocarpa

Abstract

Chloroplast DNA restriction site characters were analyzed cladistically in species of Solanum sect. Lasiocalpa (subg. Leptostemonum), and results were compared with previously published analyses of morphological and isozyme characters. Cladistic analysis of the chloroplast DNA restriction site characters resulted in a single tree in which two main clades were detected: one comprised three morphologically distinct lowland Amazonian species, and the other included the Andean and the two Asian species. Character congruence among the three data sets was assessed with a previously described index and with a permutation test derived from this index. Taxonomic congruence was evaluated with a measure modified from that of another researcher. The three assessments of congruence indicate that the chloroplast DNA and isozyme analyses are the most incongruent, but they differ as to their evaluation of relative (in)congruence for the other comparisons. Combining the three data sets resulted in two most parsimonious trees whose topologies incorporate elements from each of the separate analyses. The combined chloroplast DNA and morphological analyses support a previously proposed hypothesis that the two Asian species are sister taxa and of a single origin, rather than having originated separately from two distinct South American groups.Resume : Les auteurs ont effectuC l'analyse cladistique des caractkres des sites de restriction de 1'ADN chloroplastique chez les espkces de Solanum sect. Lasiocalpa (subg. Leptostemonum), et ils ont compare les rCsultats avec les analyses de caractkres morphologiques et isozymiques dCjB publits. L'analyse cladistique des caractkres des sites de restriction de 1'ADN chloroplastique conduit B un scul arbre dans lequel on distingue deux clades principaux: l'un comporte trois espkces des terres basses amazoniennes morphologiquement distinctes, et l'autre inclut une espkces des Andes et deux espkces asiatiques. Les auteurs ont tvalut la congruence des caractkres entre les trois ensembles de donnCes, en utilisant un index dtcrit prCcCdemment ainsi qu'un test de permutation derive de cet index. La congruence taxonomique a Ct C CvaluC avec une mesure modifiCe i partir d'une autre rechercheur. Les trois Cvaluations de congruences indiquent que les analyses de I'ADN chloroplastique et des isozymes sont les moins congruents, mais ils different quant B leur Cvaluation de la (in)congruence pour les autres comparaisons. Une combinaison des trois ensembles de donnCes a conduit aux dendrogrammes les plus parcimonieux dont les topologies incorporent des ClCments de chacune des analyses sCparCs. Les analyses combinCes de I'ADN chloroplastique et de la morphologie supportent une hypothkse dCji proposCe i l'effet que les deux espkces asiatiques constituent des taxons soeurs ayant une seule origine, plut8t que d'origines sCparCes provenant de deux groupes sud-amCricains distincts.

Systematics and Evolution of the Tropical Monocot Family Costaceae (Zingiberales): A Multiple Dataset Approach

“…The lack of well-supported resolution for each partition analyzed alone likely contributed to the lack of conflict observed in the results of the ILD test. The combined analysis is considered to be the most accurate representation of phylogenetic signal based on lack of apparent data conflict and the inherent benefits of the total evidence approach (Kluge 1989;Bruneau et al 1995;Nixon and Carpenter 1996;Graham et al 1998). Taxonomic Groupings and Support.…”

A Molecular Phylogeny of Costaceae (Zingiberales)

“…In addition, the two plastid trnK data sets arbitrarily divided at the start of the matK coding region are also found to be incongruent (P ϭ 0.01). This latter result indicates that there is significant incongruence in the data provided by one contiguous gene sequence (or "process partition"), suggesting within-data set homoplasy as another factor that can influence the results of incongruence analyses (see Bruneau et al, 1995;Siddall, 1997). It has been shown that different levels of homoplasy within data sets can render ambiguous the interpretation of P values generated by ILD or …”

“…Considering the vast amount of literature questioning the validity of partitioning data and supporting combined phylogenetic analyses (Kluge, 1989;Wheeler et al, 1993;Bruneau et al, 1995;Nixon and Carpenter, 1996;DeSalle and Brower, 1997;Siddall, 1997;Graham et al, 1998;Wenzel and Siddall, 1999), and the results obtained here with respect to the arbitrary partitioning of the data, we have decided to include all available data in a combined analysis designed to examine phylogenetic relationships for a group of organisms.…”

Phylogenetic Relationships in Solanum (Solanaceae) Based on ndhF Sequences

“…Cladistic analyses based on morphological characters exist for Solanum section Androceras (Nutt.) Marzell (Whalen 1979), section Lasiocarpa (Dunal) D'Arcy (Whalen et al 1981;Whalen and Caruso 1983;Bruneau et al 1995 (Whalen 1984), subgenus Potatoe (G. Don) D'Arcy (Spooner et al 1993), and subgenus Archaesolanum Marzell (Symon 1994). Recently, molecular phylogenetic studies have elucidated systematic problems in Solanum and the evolutionary placement of Solanum within the larger Solanoideae (Palmer and Zamir 1982;Hosaka et al 1984;Debener et al 1990;Spooner et al 1991;Olmstead and Palmer 1991, 1997Spooner and Sytsma 1992;Spooner et al 1993;Olmstead and Sweere 1994;Bruneau et al 1995;Bohs and Olmstead, in press;Olmstead et al, in press).…”