Combining data in phylogenetic analysis
TL;DR: Some of the advantages and disadvantages of the different approaches for the treatment of partitioned data are reviewed, with special concentration on which methods help to discern the evolutionary process and provide the most accurate estimates of phylogeny.
Abstract: Systematists have access to multiple sources of character information in phylogenetic analysis. For example, it is not unusual to have nucleotide sequences from several different genes, or to have molecular and morphological data. How should diverse data be analyzed in phylogenetic analysis? Several methods have been proposed for the treatment of partitioned data: the total evidence, separate analysis, and conditional combination approaches. Here, we review some of the advantages and disadvantages of the different approaches, with special concentration on which methods help us to discern the evolutionary process and provide the most accurate estimates of phylogeny.
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TL;DR: Testing whether lineages of the Panama disease pathogen have a monophyletic origin by comparing DNA sequences of nuclear and mitochondrial genes indicates Panama disease of banana is caused by fungi with independent evolutionary origins.
Abstract: Panama disease of banana, caused by the fungus Fusarium oxysporum f. sp. cubense, is a serious constraint both to the commercial production of banana and cultivation for subsistence agriculture. Previous work has indicated that F. oxysporum f. sp. cubense consists of several clonal lineages that may be genetically distant. In this study we tested whether lineages of the Panama disease pathogen have a monophyletic origin by comparing DNA sequences of nuclear and mitochondrial genes. DNA sequences were obtained for translation elongation factor 1α and the mitochondrial small subunit ribosomal RNA genes for F. oxysporum strains from banana, pathogenic strains from other hosts and putatively nonpathogenic isolates of F. oxysporum. Cladograms for the two genes were highly concordant and a partition-homogeneity test indicated the two datasets could be combined. The tree inferred from the combined dataset resolved five lineages corresponding to “F. oxysporum f. sp. cubense” with a large dichotomy between two taxa represented by strains most commonly isolated from bananas with Panama disease. The results also demonstrate that the latter two taxa have significantly different chromosome numbers. F. oxysporum isolates collected as nonpathogenic or pathogenic to other hosts that have very similar or identical elongation factor 1α and mitochondrial small subunit genotypes as banana pathogens were shown to cause little or no disease on banana. Taken together, these results indicate Panama disease of banana is caused by fungi with independent evolutionary origins.
1,639 citations
TL;DR: The results suggest that data sets consisting of single or a small number of concatenated genes have a significant probability of supporting conflicting topologies, and have important implications for resolving branches of the tree of life.
Abstract: One of the most pervasive challenges in molecular phylogenetics is the incongruence between phylogenies obtained using different data sets, such as individual genes. To systematically investigate the degree of incongruence, and potential methods for resolving it, we screened the genome sequences of eight yeast species and selected 106 widely distributed orthologous genes for phylogenetic analyses, singly and by concatenation. Our results suggest that data sets consisting of single or a small number of concatenated genes have a significant probability of supporting conflicting topologies. By contrast, analyses of the entire data set of concatenated genes yielded a single, fully resolved species tree with maximum support. Comparable results were obtained with a concatenation of a minimum of 20 genes; substantially more genes than commonly used but a small fraction of any genome. These results have important implications for resolving branches of the tree of life.
1,490 citations
TL;DR: All three tests identified cases in which improving the reconstruction model would improve the phylogenetic accuracy of the individual partitions, and the most useful was the incongruence length difference test (ILD), also called the partition homogeneity test.
Abstract: Advocates of conditional combination have argued that testing for incongruence between data partitions is an important step in data exploration. Unless the partitions have had distinct histories, as in horizontal gene transfer, incongruence means that one or more data support the wrong phylogeny. This study examines the relationship between incongruence and phylogenetic accuracy using three tests of incongruence. These tests were applied to pairs of mitochondrial DNA data partitions from two well-corroborated vertebrate phylogenies. Of the three tests, the most useful was the incongruence length difference test (ILD, also called the partition homogeneity test). This test distinguished between cases in which combining the data generally improved phylogenetic accuracy (P > 0.01) and cases in which accuracy of the combined data suffered relative to the individual partitions (P < 0.001). In contrast, in several cases, the Templeton and Rodrigo tests detected highly significant incongruence (P < 0.001) even though combining the incongruent partitions actually increased phylogenetic accuracy. All three tests identified cases in which improving the reconstruction model would improve the phylogenetic accuracy of the individual partitions.
881 citations
TL;DR: Test results show no evidence for significant differences in the phylogenetic signal among the three nuclear data sets, with the exception of the placement of a single taxon.
Abstract: Four molecular data sets are available for the diploid intersterile genera of the cereal grain tribe Triticeae, and there are numerous differences among the four published trees. All six pairwise combinations of data sets were examined using tree comparisons, the incongruence length difference test, the Wilcoxon signed ranks test, and a permutation test. We describe some advantages, disadvantages, and properties of the different comparison methods. Test results pro- vide no evidence for significant differences in the phylogenetic signal among the three nuclear data sets, with the exception of the placement of a single taxon. The chloroplast DNA restriction site data, however, support a significantly different tree, and the differences probably reflect a separate evolutionary history of the chloroplast genome. (Gramineae; incongruence length differ- ence test; permutation test; phylogenetic congruence; Poaceae; T-PTP test; Triticeae; Wilcoxon signed ranks test.) The options for handling multiple phy- logenetic data sets for the same taxa have been the focus of increasing discussion in recent years. The issue is not new, but it has become of practical concern with the greater availability of molecular data. Top- ics of discussion have included measures of dissimilarity among trees (e.g., Esta- brook et al., 1985; Penny and Hendy, 1985; Day, 1986; Lapointe and Legendre, 1992) and data sets (e.g., Mickevich and Farris, 1981; Templeton, 1983; Kluge, 1989), whether or under what circumstances multiple data sets should be combined into
805 citations
Cites background from "Combining data in phylogenetic anal..."
...Options for analyzing multiple data sets have been reviewed (Swofford, 1991; de Queiroz et al., 1995; Miyamoto and Fitch, 1995; Huelsenbeck et al., 1996)....
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TL;DR: To test whether the primary etiological agent of scab, the fungus Fusarium graminearum, is panmictic throughout its range, allelic genealogies were constructed from six single-copy nuclear genes from strains selected to represent the global genetic diversity of this pathogen.
Abstract: During the past decade, the plant disease called scab or Fusarium head blight of wheat and barley has reached epidemic proportions in North America and elsewhere in the world. Scab is an economically devastating plant disease, not only because it causes significant reduction in seed yields and quality, but also because infested seeds are often contaminated with trichothecene and estrogenic mycotoxins that pose a serious threat to animal health and food safety. To test whether the primary etiological agent of scab, the fungus Fusarium graminearum, is panmictic throughout its range, allelic genealogies were constructed from six single-copy nuclear genes from strains selected to represent the global genetic diversity of this pathogen. Excluding one hybrid strain, all six genealogies recovered the same seven biogeographically structured lineages, suggesting that they represent phylogenetically distinct species among which gene flow has been very limited during their evolutionary history. Parsimony analysis of the combined data set comprising 7,120 aligned nucleotide characters resolved most relationships among the seven lineages of the F. graminearum clade and related fusaria included in the study. Phylogenetic evidence is also presented for introgressive hybridization and intragenic recombination among lineages of the F. graminearum clade in nature.
796 citations
References
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01 Jan 1969
10,262 citations
TL;DR: A new statistical method for estimating divergence dates of species from DNA sequence data by a molecular clock approach is developed, and this dating may pose a problem for the widely believed hypothesis that the bipedal creatureAustralopithecus afarensis, which lived some 3.7 million years ago, was ancestral to man and evolved after the human-ape splitting.
Abstract: A new statistical method for estimating divergence dates of species from DNA sequence data by a molecular clock approach is developed. This method takes into account effectively the information contained in a set of DNA sequence data. The molecular clock of mitochondrial DNA (mtDNA) was calibrated by setting the date of divergence between primates and ungulates at the Cretaceous-Tertiary boundary (65 million years ago), when the extinction of dinosaurs occurred. A generalized least-squares method was applied in fitting a model to mtDNA sequence data, and the clock gave dates of 92.3 +/- 11.7, 13.3 +/- 1.5, 10.9 +/- 1.2, 3.7 +/- 0.6, and 2.7 +/- 0.6 million years ago (where the second of each pair of numbers is the standard deviation) for the separation of mouse, gibbon, orangutan, gorilla, and chimpanzee, respectively, from the line leading to humans. Although there is some uncertainty in the clock, this dating may pose a problem for the widely believed hypothesis that the pipedal creature Australopithecus afarensis, which lived some 3.7 million years ago at Laetoli in Tanzania and at Hadar in Ethiopia, was ancestral to man and evolved after the human-ape splitting. Another likelier possibility is that mtDNA was transferred through hybridization between a proto-human and a proto-chimpanzee after the former had developed bipedalism.
8,124 citations
Book•
01 Jan 1991
TL;DR: The comparative method for studying adaptation why worry about phylogeny?
Abstract: The comparative method for studying adaptation why worry about phylogeny? reconstructing phylogenetic trees and ancestral character states comparative analysis of discrete data comparative analysis of continuous variables determining the form of comparative relationships.
5,197 citations
3,857 citations