Gonadal transcriptomics elucidate patterns of adaptive evolution within marine rockfishes (Sebastes)

Area of Science:

• Marine biology
• Evolutionary genetics
• Genomics

Background:

• Genetic mechanisms of marine speciation and adaptation remain unclear.
• The rockfish genus Sebastes exhibits extensive diversity, making it a model for adaptive evolution.
• Marine adaptive radiations are unusual due to continuous gene flow.

Purpose of the Study:

• Investigate genetic signatures of natural selection in marine rockfishes.
• Identify genes involved in adaptive radiation within the Sebastes genus.
• Understand the evolutionary processes driving diversity in marine environments.

Main Methods:

• Analyzed transcriptomes from gonadal tissue of Sebastes goodei and S. saxicola.
• Predicted orthologous transcript pairs.
• Estimated nonsynonymous (Ka) and synonymous (Ks) substitution rates to detect selection.

Main Results:

• Identified 144 genes under positive selection from 1079 orthologous pairs.
• Found 11 reproduction-associated genes under positive selection, including a zona pellucida gene.
• Observed significantly lower substitution rates in 3' and 5' UTRs than Ks, indicating negative selection.

Conclusions:

• Identified candidate genes crucial for understanding adaptive radiation in Sebastes.
• Genes linked to longevity may play a role in the evolutionary radiation of this genus.
• Provides insights into the genetic basis of diversification in marine species.