Conservation of shh cis-regulatory architecture of the coelacanth is consistent with its ancestral phylogenetic positionReportar como inadecuado

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, 1:11

First Online: 03 November 2010Received: 18 May 2010Accepted: 03 November 2010


BackgroundThe modern coelacanth Latimeria is the extant taxon of a basal sarcopterygian lineage and sister group to tetrapods. Apart from certain apomorphic traits, its morphology is characterized by a high degree of retention of ancestral vertebrate structures and little morphological change. An insight into the molecular evolution that may explain the unchanged character of Latimeria morphology requires the analysis of the expression patterns of developmental regulator genes and their cis-regulatory modules CRMs.

ResultsWe describe the comparative and functional analysis of the sonic hedgehog shh genomic region of Latimeria menadoensis. Several putative enhancers in the Latimeria shh locus have been identified by comparisons to sarcopterygian and actinopterygian extant species. Specific sequence conservation with all known actinopterygian enhancer elements has been detected. However, these elements are selectively missing in more recently diverged actinopterygian and sarcopterygian species. The functionality of the putative Latimeria enhancers was confirmed by reporter gene expression analysis in transient transgenic zebrafish and chick embryos.

ConclusionsLatimeria shh CRMs represent the ancestral set of enhancers that have emerged before the split of lobe-finned and ray-finned fishes. In contrast to lineage-specific losses and differentiations in more derived lineages, Latimeria shh enhancers reveal low levels of sequence diversification. High overall sequence conservation of shh conserved noncoding elements CNE is consistent with the general trend of high levels of conservation of noncoding DNA in the slowly evolving Latimeria genome.

List of Abbreviations usedCRMscis-regulatory modules

CDScoding sequence

CNEconserved non-coding elements.

Electronic supplementary materialThe online version of this article doi:10.1186-2041-9139-1-11 contains supplementary material, which is available to authorized users.

Michael Lang, Yavor Hadzhiev contributed equally to this work.

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Autor: Michael Lang - Yavor Hadzhiev - Nicol Siegel - Chris T Amemiya - Carolina Parada - Uwe Strähle - May-Britt Becker - Feren


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