Maternally-regulated gastrulation as a source of variation contributing to cavefish forebrain evolution
- CNRS, Université Paris Sud, Université Paris-Saclay, France
Abstract
Sequential developmental events, starting from the moment of fertilization, are crucial for the acquisition of animal body plan. Subtle modifications in such early events are likely to have major impacts in later morphogenesis, bringing along morphological diversification. Here, comparing the blind cave and the surface morphotypes of Astyanax mexicanus fish, we found heterochronies during gastrulation, producing organizer and axial mesoderm tissues with different properties, including differences in expression of dkk1b, that may have contributed to cavefish brain evolution. These variations observed during gastrulation depend fully on maternal factors. The developmental evolution of retinal morphogenesis and hypothalamic patterning are among those traits that retained significant maternal influence at larval stages. Transcriptomic analysis of fertilized eggs from both morphotypes and reciprocal F1 hybrids showed a strong and specific maternal signature. Our work strongly suggests that maternal effect genes and developmental heterochronies occurring during gastrulation have impacted morphological brain change during cavefish evolution.
Data availability
Raw sequencing data are available through the NCBI Sequence Reads Archive (SRA) under BioProject accession PRJNA545230
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Maternal RNA sequencing of Astyanax mexicanus 2-cells eggsNCBI Bioproject, PRJNA545230.
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Astyanax mexicanus LIM/homeobox protein 9 mRNA, complete cdsNCBI, accession no: EF175738.1.
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Astyanax mexicanus sonic hedgehog precursor (shh) mRNA, complete cdsNCBI, accession no: EF175738.1.
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Astyanax mexicanus distal-less homeobox gene 3b (dlx3b) mRNA, partial cdsNCBI, accession no: AY661432.
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PREDICTED: Astyanax mexicanus hypocretin neuropeptide precursor (hcrt), mRNANCBI, accession no: XM_007287820.3.
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PREDICTED: Astyanax mexicanus LIM homeobox 8 (lhx8), transcript variant X1, mRNANCBI, accession no: XM_022678613.1.
Article and author information
Author details
Funding
Agence Nationale de la Recherche (blindtest)
- Sylvie Rétaux
Fondation pour la Recherche Médicale (DEQ20150331745 RETAUX)
- Sylvie Rétaux
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: Animal experimentation: Animals were treated according to the French and European regulationsfor handling of animals in research. SR's authorization for use of animals in research including Astyanax mexicanus is 91-116 and Paris Centre-Sud Ethic Committee authorization numbers are 2012-0052, -0053, and -0054.
Copyright
© 2019, Torres-Paz et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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