Colin Patterson

Bio: Colin Patterson is an academic researcher from British Museum. The author has contributed to research in topics: Incertae sedis & Lungfish. The author has an hindex of 37, co-authored 63 publications receiving 6400 citations. Previous affiliations of Colin Patterson include Guy's Hospital.

Homology in classical and molecular biology.

Abstract: Hypotheses of homology are the basis of comparative morphology and comparative molecular biology. The kinds of homologous and nonhomologous relations in classical and molecular biology are explored through the three tests that may be applied to a hypothesis of homology: congruence, conjunction, and similarity. The same three tests apply in molecular comparisons and in morphology, and in each field they differentiate eight kinds of relation. These various relations are discussed and compared. The unit or standard of comparison differs in morphology and in molecular biology; in morphology it is the adult or life cycle, but with molecules it is the haploid genome. In morphology the congruence test is decisive in separating homology and nonhomology, whereas with molecular sequence data similarity is the decisive test. Consequences of this difference are that the boundary between homology and nonhomology is not the same in molecular biology as in morphology, that homology and synapomorphy can be equated in morphology but not in all molecular comparisons, and that there is no detected molecular equivalent of convergence. Since molecular homology may reflect either species phylogeny or gene phylogeny, there are more kinds of homologous relation between molecular sequences than in morphology. The terms paraxenology and plerology are proposed for two of these kinds--respectively, the consequence of multiple xenology and of gene conversion.

Percomorph phylogeny: a survey of acanthomorphs and a new proposal

Abstract: The interrelationships of acanthomorph fishes are reviewed. We recognize seven monophyletic terminal taxa among acanthomorphs: Lampridiformes, Polymixiiformes, Paracanthopterygii, Stephanoberyciformes, Beryciformes, Zeiformes, and a new taxon named Smegmamorpha. The Percomorpha, as currently constituted, are polyphyletic, and the Perciformes are probably paraphyletic. The smegmamorphs comprise five subgroups: Synbranchiformes (Synbranchoidei and Mastacembeloidei), Mugilomorpha (Mugiloidei), Elassomatidae (Elassoma), Gasterosteiformes, and Atherinomorpha. Monophyly of Lampridiformes is justified elsewhere; we have found no new characters to substantiate the monophyly of Polymixiiformes (which is not in doubt) or Paracanthopterygii. Stephanoberyciformes uniquely share a modification of the extrascapular, and Beryciformes a modification of the anterior part of the supraorbital and infraorbital sensory canals, here named Jakubowski's organ. Our Zeiformes excludes the Caproidae, and characters are proposed to justify the monophyly of the group in that restricted sense. The Smegmamorpha are thought to be monophyletic principally because of the configuration of the first vertebra and its intermuscular bone. Within the Smegmamorpha, the Atherinomorpha and Mugilomorpha are shown to be monophyletic elsewhere. Our Gasterosteiformes includes the syngnathoids and the Pegasiformes (Pegasus) and Indostomiformes (lndostomus), two groups which are shown to be immediately related to syngnathoids by modifications of the gill filaments and their skeletal supports. Monophyly of the Gasterosteiformes in this sense is justified by several characters. We are unable to resolve the interrelationships among the five subgroups of Smegmamorpha. The remaining percomorphs are the Perciformes (including Caproidae), Scorpaeniformes, Dactylopteriformes, Pleuronectiformes and Tetraodontiformes; we have found nothing to indicate that Percomorphain that sense are monophyletic, although our survey does not cover Tetraodontiformes. We believe that Scorpaeniformes and Pleuronectiformes are nested within Perciformes, but again have found nothing to indicate that Perciformes in this expanded sense are monophyletic. We recommend extending the Percomorpha to include the Atherinomorpha (and other smegmamorphs), and argue that this larger group is monophyletic. A scheme of relationships of the seven groups Lampridiformes, Polymixiiformes, Paracanthopterygii, Stephanoberyciformes, Zeiformes, Beryciformes and the expanded Percomorpha is presented and supported by apomorphies. New names for higher acanthomorph taxa are proposed as follows: Euacanthomorpha (Acanthomorpha minus Lampridiformes), Holacanthopterygii (Eucanthomorpha minus Polymixiiformes), and Euacanthopterygii (Acanthopterygii minus Stephanoberyciformes). Monophyly of Beryciformes s.1. (including stephanoberyciforms) is rejected because Beryciformes s.s. share several apomorphies with the expanded Percomorpha, all of which are absent in Stephanoberyciformes. The Zeiformes are the most problematic of the acanthomorph groups; with the characters that we have been able to assess, the zeiforms are placed most parsimoniously as the sister-group of Euacanthopterygii (i.e., between stephanoberyciforms and beryciforms on the cladogram), but we do not propose a name for the taxon so formed. There is a disturbing incidence of homoplasy in the characters that we have investigated in acanthomorphs. Fishes, considered collectively ... offer to the philosopher an endless source of meditation and surprise. J.-A. Brillat-Savarin, "The Philosopher in the Kitchen," 1825. Thus, recent work has resolved the bush at the bottom, but the bush at the top persists. G. Nelson (1989: 328).

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Ribosomal DNA: molecular evolution and phylogenetic inference.

Abstract: Ribosomal DNA (rDNA) sequences have been aligned and compared in a number of living organisms, and this approach has provided a wealth of information about phylogenetic relationships. Studies of rDNA sequences have been used to infer phylogenetic history across a very broad spectrum, from studies among the basal lineages of life to relationships among closely related species and populations. The reasons for the systematic versatility of rDNA include the numerous rates of evolution among different regions of rDNA (both among and within genes), the presence of many copies of most rDNA sequences per genome, and the pattern of concerted evolution that occurs among repeated copies. These features facilitate the analysis of rDNA by direct RNA sequencing, DNA sequencing (either by cloning or amplification), and restriction enzyme methodologies. Constraints imposed by secondary structure of rRNA and concerted evolution need to be considered in phylogenetic analyses, but these constraints do not appear to impede seriously the usefulness of rDNA. An analysis of aligned sequences of the four nuclear and two mitochondrial rRNA genes identified regions of these genes that are likely to be useful to address phylogenetic problems over a wide range of levels of divergence. In general, the small subunit nuclear sequences appear to be best for elucidating Precambrian divergences, the large subunit nuclear sequences for Paleozoic and Mesozoic divergences, and the organellar sequences of both subunits for Cenozoic divergences. Primer sequences were designed for use in amplifying the entire nuclear rDNA array in 15 sections by use of the polymerase chain reaction; these "universal" primers complement previously described primers for the mitochondrial rRNA genes. Pairs of primers can be selected in conjunction with the analysis of divergence of the rRNA genes to address systematic problems throughout the hierarchy of life.

Gaps as Characters in Sequence-Based Phylogenetic Analyses

Abstract: In the analysis of sequence-based data matrices, the use of different methods of treating gaps has been demonstrated to in? fluence the resulting phylogenetic hypothe? ses (e.g., Eernisse and Kluge, 1993; Vogler and DeSalle, 1994; Simons and Mayden, 1997). Despite this influence, a well-justi? fied, uniformly applied method of treating gaps is lacking in sequence-based phyloge? netic studies. Treatment of gaps varies widely from secondarily mapping gaps onto the tree inferred from base characters

The amphibian tree of life

Abstract: The evidentiary basis of the currently accepted classification of living amphibians is discussed and shown not to warrant the degree of authority conferred on it by use and tradition. A new taxonomy of living amphibians is proposed to correct the deficiencies of the old one. This new taxonomy is based on the largest phylogenetic analysis of living Amphibia so far accomplished. We combined the comparative anatomical character evidence of Haas (2003) with DNA sequences from the mitochondrial transcription unit H1 (12S and 16S ribosomal RNA and tRNAValine genes, ≈ 2,400 bp of mitochondrial sequences) and the nuclear genes histone H3, rhodopsin, tyrosinase, and seven in absentia, and the large ribosomal subunit 28S (≈ 2,300 bp of nuclear sequences; ca. 1.8 million base pairs; x = 3.7 kb/terminal). The dataset includes 532 terminals sampled from 522 species representative of the global diversity of amphibians as well as seven of the closest living relatives of amphibians for outgroup comparisons. The...

A Concern for Evidence and a Phylogenetic Hypothesis of Relationships among Epicrates (Boidae, Serpentes)

Abstract: -Character congruence, the principle of using all the relevant data, and character independence are important concepts in phylogenetic inference, because they relate directly to the evidence on which hypotheses are based. Taxonomic congruence, which is agreement among patterns of taxonomic relationships, is less important, because its connection to the underlying character evidence is indirect and often imperfect. Also, taxonomic congruence is difficult to justify, because of the arbitrariness involved in choosing a consensus method and index with which to estimate agreement. High levels of character congruence were observed among 89 biochemical and morphological synapomorphies scored on 10 species of Epicrates. Such agreement is consistent with the phylogenetic interpretation attached to the resulting hypothesis, which is a consensus of two equally parsimonious cladograms: (cenchria (angulifer (striatus ((chrysogaster, exsul) (inornatus, subflavus) (gracilis (fordii, monensis)))))). Relatively little (11.4%) of the character incongruence was due to the disparity between the biochemical and morphological data sets. Each of the clades in the consensus cladogram was confirmed by two or more unique and unreversed novelties, and six of the eight clades were corroborated by biochemical and morphological evidence. Such combinations of characters add confidence to the phylogenetic hypothesis, assuming the qualitatively different kinds of data are more likely to count as independent than are observations drawn from the same character system. Most of the incongruence occurred in the skeletal subset of characters, and much of that independent evolution seemed to be the result of paedomorphosis. [Biochemical data; character congruence; character independence; Epicrates; evidence; morphological data; paedomorphosis; phylogenetic systematics; taxonomic congruence; total evidence.] The goals of cladistics and phenetics are different. The former estimates phylogeny (Hennig, 1966), the latter seeks stability and convenience in classification (Sokal, 1986:424). Unfortunately, these objectives have become confused, especially where stability is concerned. For example, Hillis (1987:35) stated that "[c]lassifications are best based on information in common among multiple data sets (i.e., consensus trees), whereas the best estimate of phylogeny and best estimate of character evolution are represented in the analysis of the combined data sets." The importance of a conservative information storage-retrieval system is undeniable (e.g., International Code of Zoological Nomenclature, 1985:3), and pheneticists sought justification for their methods in this simple truth (Sokal and Sneath, 1963). Even cladists attributed some significance to stability per se, because the lack of it confounds attempts to discover the single historical pattern (Schuh and Farris, 1981). Not unexpectedly, cladists responded (e.g., Farris, 1971) to the proposition that phenetic methods produce more stable classifications (e.g., Sokal and Sneath, 1963: 264). Analytical precision was demanded by the contestants, and an incredible array of consensus methods and indexes were developed (see lists below). It is important to bear in mind that only information on taxonomic grouping can be used to evaluate the pheneticists' claims, because character congruence is difficult to judge in phenetic analyses. Eventually, the controversy over stability became a relative issue, with cladists arguing greater stability for classifications produced by their methods, as if stability was a goal of phylogenetic systematics. Further, Nelson and Platnick (1981:219; see also Nelson, 1979) attempted to justify cla-