Consilience of independent phylogenies

Consilience of independent phylogenies - Consilience of...

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Consilience of independent phylogenies "It will be determined to what extent the phylogenetic tree, as derived from molecular data in complete independence from the results of organismal biology, coincides with the phylogenetic tree constructed on the basis of organismal biology. If the two phylogenetic trees are mostly in agreement with respect to the topology of branching, the best available single proof of the reality of macro-evolution would be furnished. Indeed, only the theory of evolution, combined with the realization that events at any supramolecular level are consistent with molecular events, could reasonably account for such a congruence between lines of evidence obtained independently, namely amino acid sequences of homologous polypeptide chains on the one hand, and the finds of organismal taxonomy and paleontology on the other hand. Besides offering an intellectual satisfaction to some, the advertising of such evidence would of course amount to beating a dead horse. Some beating of dead horses may be ethical, when here and there they display unexpected twitches that look like life." Emile Zuckerkandl and Linus Pauling , discussing the possibility of the twin nested hierarchy before the first molecular phylogenies had been made. (1965) "Evolutionary Divergence and Convergence in Proteins." in Evolving Genes and Proteins , p. 101. Here we commence to beat Pauling's poor 40-year dead horse. If there is one historical phylogenetic tree which unites all species in an objective genealogy, all separate lines of evidence should converge on the same tree (Penny et al . 1982 ; Penny et al . 1991 ; Zuckerkandl and Pauling 1965 ). Independently derived phylogenetic trees of all organisms should match each other with a high degree of statistical significance. Confirmation: Well-determined phylogenetic trees inferred from the independent evidence of morphology and molecular sequences match with an extremely high degree of statistical significance. Many genes with very basic cellular functions are ubiquitous—they occur in the genomes of most or all organisms. An oft-cited example is the cytochrome c gene. Since all eukaryotes contain the gene for this essential protein, neither its presence nor its function correlates with organismal morphology. Additionally, because of the fact of DNA coding redundancy, parts of certain DNA sequences have absolutely no correlation with phenotype (e.g. certain introns or the four-fold degenerate third-base position of most DNA codons). Due to these two aspects of certain DNA sequences, ubiquity and redundancy, DNA sequences can be carefully chosen that constitute completely independent data from morphology. (See point 17 and 18 for more background about the molecular sequence evidence and for more detail about how it is independent of morphology.) The degree of phylogenetic congruence between these independent data sets is nothing short of incredible. In science, independent measurements of theoretical values are never exact. When inferring any
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This note was uploaded on 11/14/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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Consilience of independent phylogenies - Consilience of...

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