Genetic and Developmental Divergence in the Neural Crest Program between Cichlid Fish Species

Area of Science:

• Evolutionary developmental biology
• Comparative genomics
• Vertebrate embryology

Background:

• Neural crest (NC) cells are crucial for vertebrate development, forming structures like the craniofacial skeleton and pigment patterns.
• The role of NC evolution in generating species diversity, especially in vertebrates, is not well understood.

Purpose of the Study:

• Investigate the evolution of the NC genetic program in cichlid fish to understand morphological divergence.
• Identify genes, particularly sox10 paralogs, involved in NC development and their contribution to species-specific traits.

Main Methods:

• Comparative transcriptomics and population genomics in African cichlid species.
• Analysis of gene expression differences during somitogenesis.
• CRISPR/Cas9 mutagenesis to study sox10 paralog function.

Main Results:

• Significant differences in transcriptional landscapes related to NC development were found across cichlid species.
• Teleost-specific sox10 paralogs (sox10a and sox10b) showed spatio-temporal variation and signs of positive selection.
• Functional divergence was observed between sox10 paralogs, with sox10a acquiring a novel skeletogenic role.

Conclusions:

• Neural crest evolution, particularly involving sox10 genes, plays a significant role in generating morphological diversity among vertebrate species.
• The functional evolution of sox10 paralogs varies across teleost phylogeny, contributing to species-specific traits like craniofacial structures and pigmentation.