Comparative transcriptome analysis reveals vertebrate phylotypic period during organogenesis
Naoki Irie & Shigeru Kuratani
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Nature Communications 2, Article number: 248
doi:10.1038/ncomms1248
Received 11 November 2010 Accepted 21 February 2011 Published 22 March 2011
Abstract
One of the central issues in evolutionary developmental biology is how we can formulate the relationships between evolutionary and developmental processes. Two major models have been proposed: the 'funnel-like' model, in which the earliest embryo shows the most conserved morphological pattern, followed by diversifying later stages, and the 'hourglass' model, in which constraints are imposed to conserve organogenesis stages, which is called the phylotypic period. Here we perform a quantitative comparative transcriptome analysis of several model vertebrate embryos and show that the pharyngula stage is most conserved, whereas earlier and later stages are rather divergent. These results allow us to predict approximate developmental timetables between different species, and indicate that pharyngula embryos have the most conserved gene expression profiles, which may be the source of the basic body plan of vertebrates.
Subject terms: Biological Sciences, Bioinformatics, Developmental biology, Evolution
Introduction
The relationship between ontogeny and phylogeny has long been an intriguing question in comparative and evolutionary embryology1. Biogenetic law of Ernst Haeckel assumed a parallelism between ontogeny and phylogeny, and asserted that embryogenesis is a recapitulation of ancient organisms because all animals start their existence from a one-celled stage and develop into morula, blastula and then gastrula stages2, 3. Although it is now widely accepted that embryogenesis cannot simply be a repetition of evolution, none of the alternative formulations has reached a consensus, even with contemporary evolutionary developmental ('evo-devo') theories2. For example, we still do not know how to explain the common early embryonic stages, such as the morula, blastula and gastrula, in evolutionary terms. Is this because earlier stages of embryogenesis tend to be more evolutionarily conserved? One of the major controversies, which are limiting the formulation of an evolutionary model of embryogenesis, is whether the earliest or organogenesis phase of the embryonic period is more resistant to evolutionary change and, hence, more conserved among vertebrate embryos (Fig. 1).
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NOTA DESTE BLOGGER:
Depois do livro Icons of Evolution, de Jonathan Wells, e desta pesquisa espera-se que na abordagem da teoria da evolução estes embriões não apareçam mais como prova do fato, Fato, FATO (obrigado Michael Ruse pela pérola linguística) da evolução.
Pensar que autores de livros didáticos visitam este blog para se atualizarem em biologia evolutiva... Espero que eles sejam mais cientificamente honestos sobre a abordagem da evolução em seus livros didáticos!!!
Pensar que autores de livros didáticos visitam este blog para se atualizarem em biologia evolutiva... Espero que eles sejam mais cientificamente honestos sobre a abordagem da evolução em seus livros didáticos!!!
