Alternative splicing in parallel evolution and the evolutionary potential in sticklebacks.

Area of Science:

• Evolutionary Biology
• Genomics
• Molecular Biology

Background:

• Natural selection's predictability is studied through repeated adaptation to similar environments.
• Gene expression differences in adaptation are well-studied, but post-transcriptional regulation, like alternative splicing, is less understood in parallel adaptation.

Purpose of the Study:

• To evaluate the role of alternative splicing in parallel adaptation.
• To compare the genetic architecture and biological processes of parallelly expressed and spliced genes.
• To assess the evolutionary potential of gene expression versus alternative splicing.

Main Methods:

• Reanalysis of transcriptomic data from threespine stickleback (Gasterosteus aculeatus) ecotypes.
• Identification of genes with repeated expression or splicing divergence across marine and freshwater ecotype pairs.
• Comparison of genetic architecture, biological processes, and nucleotide diversity between parallelly expressed and spliced genes.

Main Results:

• Both differential splicing and expression showed parallel divergence, with splicing exhibiting lower parallelism than expression.
• Parallel splicing and expression divergences involved distinct genetic variants and gene sets.
• Parallelly spliced genes had higher nucleotide diversity than parallelly expressed genes, suggesting splicing is less prone to erosion.

Conclusions:

• Alternative splicing contributes uniquely to parallel adaptation.
• Splicing variation has a significant role in the evolutionary potential of wild populations facing environmental change.
• Understanding splicing is crucial for predicting evolutionary responses to environmental shifts.