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Genome-enabled discovery of evolutionary divergence in brains and behavior
Chinar Patil1, Jonathan B Sylvester2,3, Kawther Abdilleh2
1School of Biological Sciences and Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA. cpatil6@gatech.edu.
Scientific Reports
|June 22, 2021
Summary
Lake Malawi cichlid fish genomes reveal key genetic variants driving evolutionary changes in form and function. These non-coding DNA changes impact brain development and behavior, showcasing evolutionary reverse genetics.
Area of Science:
- Evolutionary biology
- Genomics
- Neuroscience
Background:
- Lake Malawi cichlid fishes display remarkable diversity in form and function.
- This divergence is attributed to a limited number of genetic alterations.
Purpose of the Study:
- To identify genetic variants differentiating rock- and sand-dwelling cichlid species.
- To investigate the role of these variants in phenotypic divergence, specifically in brain development and behavior.
Main Methods:
- Comparative genomics of rock- and sand-dwelling cichlid species.
- Analysis of non-coding genetic variants and their evolutionary conservation.
- Functional studies using species and hybrids to examine gene expression and developmental pathways (BMP signaling, irx1b).
Main Results:
- 96% of differentiated genetic variants were found in non-coding DNA, yet these variants are evolutionarily conserved.
- Genome regions near differentiated variants are enriched for genes related to craniofacial, neural, and behavioral development.
- Identified roles for BMP signaling and irx1b in forebrain development and revealed context-dependent brain gene expression during social behavior.
Conclusions:
- Divergent non-coding genome sequences can predict significant differences in key evolutionary traits.
- Evolutionary reverse genetics, combining genome sequencing with empirical validation, is a powerful approach to understand phenotypic divergence.
- Genetic changes in non-coding DNA play a crucial role in the rapid evolution of cichlid fishes.
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