From Cnidaria to Higher Metazoa in one step

The origin of multicellular animals and how multicellularity evolved is one of those difficult and delicate biological problems that has been pondered over for centuries. This book attempts to summarize some of the more recent results in phylogenetics and developmental biology that address the evolution of key innovations in metazoans. The book has three main sections. The first section contains five chapters that address the phylogenetic issues involving this part of the tree of life. Even though modern genome technology has made it possible to study these issues using a vast information database the elucidation of the relationships in this part of the tree of life continues to be elusive. The second section of the book addresses some of the more prominent questions concerning the developmental biology of metazoan evolution. The topics in this section focus on nervous system development, sensory organ development and developmental systems. The third section of the book focuses on the evolution of pattern and process in the incredible forms of life that we call Metazoa. The topics covered in this part of the book include the evolution of life histories, ecological associations and the evolution of biogeochmical aspects of metazoa. The book has over 40 illustrations and an up to date bibliography of over 500 references. Each chapter concludes with a set of questions for study and discussion to assist instructors and students in delving more deeply into the topics covered by the seventeen chapters in the book. Table of Contents Introduction: A Phylogenomic Journey Through the Animal Tree of Life: Key Innovations in the Evolution of Metazoa; B. Schierwater and R. DeSalle Tangled Roots in the Animal Tree of Life Putting Animals in their Place Within a Context of Eukaryotic Innovations; D. Vazquez, L. Wegener Parfrey and L.A. Katz Elucidating Animal Phylogeny: Advances in Knowledge and Forthcoming Challenges; K.M. Kocot, J.T. Cannon and K.M. Halanych Key Transitions in Animal Evolution: a Mitochondrial DNA Perspective; D.V. Lavrov Pending Issues in Development and Phylogeny of Arthropods; J.S. Deutsch The Earliest Animals: From Genes to Transitions The Pre-nervous System and Beyond—Poriferan Milestones in the Early Evolution of the Metazoan Nervous System; M. Nickel A Key Innovation in Evolution, the Emergence of Neurogenesis: Cellular and Molecular Cues from Cnidarian Nervous Systems; B. Galliot, M. Quiquand, M. Miljkovic-Licina and S. Chera From Cnidaria to "Higher Metazoa" in One Step; F. Boero and S. Piraino Basal Metazoan Sensory Evolution; D.K. Jacobs, D.A. Gold, N. Nakanishi, D. Yuan, A. Camara, S.A. Nichols and V. Hartenstein Cnidarian Gene Expression Patterns and the Origins of Bilaterality—Are Cnidarians Reading the Same Game Plan as "Higher" Animals?; E.E. Ball, D.M. de Jong, B. Schierwater, C. Shinzato, D.C. Hayward and D.J. Miller Key Transitions During Animal Phototransduction Evolution: Co-duplication as a Null Hypothesis for the Evolutionary Origins of Novel Traits; T.H. Oakley and D.C. Plachetzki Vertebrate Hox Genes and Specializations in Mammals; C. Kappen Pattern and Process at the Base of the Metazoan Tree of Life Field Biology of Placozoans (Trichoplax): Distribution, Diversity, Biotic Interactions; V. Buchsbaum Pearse and O. Voigt Trichoplax and Placozoa: One of the Crucial Keys to Understanding Metazoan Evolution; B. Schierwater et al. A Food’s-Eye View of Animal Transitions; N.W. Blackstone Lost in Transition: The Biogeochemical Context of Animal Origins; E. Gaidos Redefining Stem Cells and Assembling Germ Plasm: Key Transitions in the Evolution of the Germ Line; J. Srouji and C. Extavour Questions and Discussio

Phylogenetic analysis of phenotypic characters of Tunicata supports basal Appendicularia and monophyletic Ascidiacea

With approximately 3000 marine species, Tunicata represents the most disparate subtaxon of Chordata. Molecular phylogenetic studies support Tunicata as sister taxon to Craniota, rendering it pivotal to understanding craniate evolution. Although successively more molecular data have become available to resolve internal tunicate phylogenetic relationships, phenotypic data have not been utilized consistently. Herein these shortcomings are addressed by cladistically analyzing 117 phenotypic characters for 49 tunicate species comprising all higher tunicate taxa, and five craniate and cephalochordate outgroup species. In addition, a combined analysis of the phenotypic characters with 18S rDNA ‐sequence data is performed in 32 OTU s. The analysis of the combined data is congruent with published molecular analyses. Successively up‐weighting phenotypic characters indicates that phenotypic data contribute disproportionally more to the resulting phylogenetic hypothesis. The strict consensus tree from the analysis of the phenotypic characters as well as the single most parsimonious tree found in the analysis of the combined dataset recover monophyletic Appendicularia as sister taxon to the remaining tunicate taxa. Thus, both datasets support the hypothesis that the last common ancestor of Tunicata was free‐living and that ascidian sessility is a derived trait within Tunicata. “Thaliacea” is found to be paraphyletic with Pyrosomatida as sister taxon to monophyletic Ascidiacea and the relationship between Doliolida and Salpida is unresolved in the analysis of morphological characters; however, the analysis of the combined data reconstructs Thaliacea as monophyletic nested within paraphyletic “Ascidiacea”. Therefore, both datasets differ in the interpretation of the evolution of the complex holoplanktonic life history of thaliacean taxa. According to the phenotypic data, this evolution occurred in the plankton, whereas from the combined dataset a secondary transition into the plankton from a sessile ascidian is inferred. Besides these major differences, both analyses are in accord on many phylogenetic groupings, although both phylogenetic reconstructions invoke a high degree of homoplasy. In conclusion, this study represents the first serious attempt to utilize the potential phylogenetic information present in phenotypic characters to elucidate the inter‐relationships of this diverse marine taxon in a consistent cladistic framework.Peer Reviewe

Measuring the Efficiency of the Intraday Forex Market with a Universal Data Compression Algorithm

Efficient Market Hypothesis, Universal prediction, Forex Intra-day trading, Variable Order Markov, G14, C22, C53, C49, C63, 62P05, 91B84, 62M20,

Cnidarian gene expression patterns and the origins of bilaterality – are cnidarians reading the same game plan as "higher" animals?

[Extract] The past few years have seen a dramatic increase in the available data on gene sequence and gene expression for cnidarians and other "lower" Metazoa, and a flurry of recent papers has drawn on these to address the origins of bilaterality. Cnidarianhomologs of many genes that play key roles in the specification of both the A/P and D/V axes of bilaterians have been characterized, and their patterns of expression determined. Some of these expression patterns are consistent with the conservation of function between Cnidaria and Bilateria, but others clearly differ. Moreover, in some cases very different interpretations have been made on the basis of the same, or similar,\ud data. In part, these differences reflect the inevitable uncertainties associated with the depth of the divergence between cnidarians and bilaterians. In this paper we briefly summarize the cnidarian data on gene expression\ud and organization relevant to axis formation, the varying interpretations of these data, and where they conflict. Our conclusion is that the oral-aboral axis probably does correspond to the anterior-posterior axis of bilaterians,\ud but that its polarity remains uncertain, and that many of the same genes are involved in determining the directive axis of cnidarians and the dorsal-ventral axis of bilaterians, but with sufficient differences in expression that exact homologies are uncertain