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Unexpected co-linearity of Hox gene expression in an aculiferan mollusk

BACKGROUND: Mollusca is an extremely diverse animal phylum that includes the aculiferans (worm-like aplacophorans and eight-shelled polyplacophorans) and their sister group, the conchiferans, comprising monoplacophorans, bivalves (clams, mussels), gastropods (snails, slugs), scaphopods (tusk shells)...

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Autores principales: Fritsch, M., Wollesen, T., de Oliveira, A.L., Wanninger, A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524011/
https://www.ncbi.nlm.nih.gov/pubmed/26243538
http://dx.doi.org/10.1186/s12862-015-0414-1
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author Fritsch, M.
Wollesen, T.
de Oliveira, A.L.
Wanninger, A.
author_facet Fritsch, M.
Wollesen, T.
de Oliveira, A.L.
Wanninger, A.
author_sort Fritsch, M.
collection PubMed
description BACKGROUND: Mollusca is an extremely diverse animal phylum that includes the aculiferans (worm-like aplacophorans and eight-shelled polyplacophorans) and their sister group, the conchiferans, comprising monoplacophorans, bivalves (clams, mussels), gastropods (snails, slugs), scaphopods (tusk shells) and cephalopods (squids, octopuses). Studies on mollusks have revealed an overall number of 11 Hox genes in seven out of eight molluscan “class”-level taxa, but expression data of key developmental regulators such as homeotic genes are only available for three gastropod and two cephalopod species. These show that Hox genes are involved in the formation of specific features including shell, foot, funnel or tentacles and not in antero-posterior body plan patterning as in most other bilaterian animals. The role of Hox genes in non-conchiferan (i.e., aculiferan) mollusks remains entirely unknown. RESULTS: Here we present the first data on the expression of seven Hox genes in apolyplacophoran mollusk, Acanthochitona crinita. In A. crinita the Hox genes Acr-Hox1-5, Hox7 and Post2 are expressed in a co-linear pattern along the antero-posterior axis, but not in molluscan-specific features such as the shell or the foot. The expression pattern is restricted to the post-trochal region and the transcripts are present in ecto-, endo- and mesodermal cell layers. Contrary to the situation in gastropods and cephalopods, we did neither find Hox gene expression in distinct neural subsets of A. crinita, nor in its developing shell plates. CONCLUSIONS: Our analysis and comparison with other lophotrochozoans indicate that the basal role of Hox genes is in antero-posterior axis patterning in mollusks, similar to the vast majority of bilaterian animals, and that this role has been conserved in polyplacophorans, while co-option into patterning of evolutionary novelties emerged either at the base of Conchifera or independently in gastropods and cephalopods. These morphological innovations most likely contributed to the evolutionary success of its representatives, as exemplified by, e.g., the wide ecological range and species richness of gastropods.
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spelling pubmed-45240112015-08-05 Unexpected co-linearity of Hox gene expression in an aculiferan mollusk Fritsch, M. Wollesen, T. de Oliveira, A.L. Wanninger, A. BMC Evol Biol Research Article BACKGROUND: Mollusca is an extremely diverse animal phylum that includes the aculiferans (worm-like aplacophorans and eight-shelled polyplacophorans) and their sister group, the conchiferans, comprising monoplacophorans, bivalves (clams, mussels), gastropods (snails, slugs), scaphopods (tusk shells) and cephalopods (squids, octopuses). Studies on mollusks have revealed an overall number of 11 Hox genes in seven out of eight molluscan “class”-level taxa, but expression data of key developmental regulators such as homeotic genes are only available for three gastropod and two cephalopod species. These show that Hox genes are involved in the formation of specific features including shell, foot, funnel or tentacles and not in antero-posterior body plan patterning as in most other bilaterian animals. The role of Hox genes in non-conchiferan (i.e., aculiferan) mollusks remains entirely unknown. RESULTS: Here we present the first data on the expression of seven Hox genes in apolyplacophoran mollusk, Acanthochitona crinita. In A. crinita the Hox genes Acr-Hox1-5, Hox7 and Post2 are expressed in a co-linear pattern along the antero-posterior axis, but not in molluscan-specific features such as the shell or the foot. The expression pattern is restricted to the post-trochal region and the transcripts are present in ecto-, endo- and mesodermal cell layers. Contrary to the situation in gastropods and cephalopods, we did neither find Hox gene expression in distinct neural subsets of A. crinita, nor in its developing shell plates. CONCLUSIONS: Our analysis and comparison with other lophotrochozoans indicate that the basal role of Hox genes is in antero-posterior axis patterning in mollusks, similar to the vast majority of bilaterian animals, and that this role has been conserved in polyplacophorans, while co-option into patterning of evolutionary novelties emerged either at the base of Conchifera or independently in gastropods and cephalopods. These morphological innovations most likely contributed to the evolutionary success of its representatives, as exemplified by, e.g., the wide ecological range and species richness of gastropods. BioMed Central 2015-08-05 /pmc/articles/PMC4524011/ /pubmed/26243538 http://dx.doi.org/10.1186/s12862-015-0414-1 Text en © Fritsch et al. 2015 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Fritsch, M.
Wollesen, T.
de Oliveira, A.L.
Wanninger, A.
Unexpected co-linearity of Hox gene expression in an aculiferan mollusk
title Unexpected co-linearity of Hox gene expression in an aculiferan mollusk
title_full Unexpected co-linearity of Hox gene expression in an aculiferan mollusk
title_fullStr Unexpected co-linearity of Hox gene expression in an aculiferan mollusk
title_full_unstemmed Unexpected co-linearity of Hox gene expression in an aculiferan mollusk
title_short Unexpected co-linearity of Hox gene expression in an aculiferan mollusk
title_sort unexpected co-linearity of hox gene expression in an aculiferan mollusk
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524011/
https://www.ncbi.nlm.nih.gov/pubmed/26243538
http://dx.doi.org/10.1186/s12862-015-0414-1
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