1. Evolution of the regulation of developmental gene expression in blind Mexican cavefish.
- Author
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Leclercq J, Torres-Paz J, Policarpo M, Agnès F, and Rétaux S
- Subjects
- Animals, Biological Evolution, Caves, Fish Proteins genetics, Fish Proteins metabolism, Gastrulation genetics, Evolution, Molecular, Gene Expression Regulation, Developmental, Characidae genetics, Characidae embryology, Transcriptome genetics
- Abstract
Developmental evolution and diversification of morphology can arise through changes in the regulation of gene expression or protein-coding sequence. To unravel mechanisms underlying early developmental evolution in cavefish of the species Astyanax mexicanus, we compared transcriptomes of surface-dwelling and blind cave-adapted morphs at the end of gastrulation. Twenty percent of the transcriptome was differentially expressed. Allelic expression ratios in cave X surface hybrids showed that cis-regulatory changes are the quasi-exclusive contributors to inter-morph variations in gene expression. Among a list of 108 genes with change at the cis-regulatory level, we explored the control of expression of rx3, which is a master eye gene. We discovered that cellular rx3 levels are cis-regulated in a cell-autonomous manner, whereas rx3 domain size depends on non-autonomous Wnt and Bmp signalling. These results highlight how uncoupled mechanisms and regulatory modules control developmental gene expression and shape morphological changes. Finally, a transcriptome-wide search for fixed coding mutations and differential exon use suggested that variations in coding sequence have a minor contribution. Thus, during early embryogenesis, changes in gene expression regulation are the main drivers of cavefish developmental evolution., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)
- Published
- 2024
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