Extensive Differential Splicing Underlies Phenotypically Plastic Aphid Morphs.

Area of Science:

• Molecular Biology
• Evolutionary Biology
• Genetics

Background:

• Phenotypic plasticity allows a single genotype to produce diverse phenotypes based on environmental cues.
• Research on phenotypic plasticity has primarily focused on differential gene expression, largely overlooking alternative splicing.
• Alternative splicing's role in generating distinct phenotypes within environmentally cued polyphenisms remains understudied.

Purpose of the Study:

• To investigate alternative splicing differences between distinct polyphenic morphs of the pea aphid.
• To determine the extent and nature of differential splicing in environmentally induced phenotypes.
• To identify candidate genes involved in phenotypic plasticity through alternative splicing.

Main Methods:

• Utilized RNA-sequencing data from genetically identical pea aphids exhibiting distinct polyphenisms.
• Analyzed alternative splicing events, including exon skipping and mutually exclusive exon usage.
• Compared differentially spliced genes with differentially expressed genes.

Main Results:

• Pea aphids exhibit a high rate of alternative splicing, with 34% of genes undergoing this process.
• Extensive differential splicing events were observed between polyphenic morphs, distinct from differential gene expression.
• Differentially spliced genes are enriched for events maintaining open reading frames, suggesting phenotype-biased protein production.
• Many differentially spliced genes possess functions relevant to the specific phenotypes (e.g., ensconsin, CAKI).

Conclusions:

• Alternative splicing plays a significant role in the expression of environmentally determined phenotypes in pea aphids.
• This study highlights the importance of alternative splicing beyond gene expression for understanding phenotypic plasticity.
• Provides a valuable list of candidate genes for future functional studies on polyphenisms.