Correcting for differential transcript coverage reveals a strong relationship between alternative splicing and...

Area of Science:

• Genomics
• Evolutionary Biology
• Molecular Biology

Background:

• Organism complexity is a fundamental question in biology.
• Genomic features linked to complexity are actively researched.
• Alternative splicing's role in complexity has been hypothesized but not empirically established.

Purpose of the Study:

• To investigate the relationship between alternative splicing and organism complexity.
• To establish a comparable index for alternative splicing across species.
• To determine if alternative splicing predicts organism complexity.

Main Methods:

• Analyzed over 39 million expressed sequence tags from 47 eukaryotic species.
• Developed a novel index for alternative splicing estimates, correcting for transcript number variation.
• Assayed organism complexity by the number of cell types.

Main Results:

• Alternative splicing has increased over the last 1.4 billion years of eukaryotic evolution.
• A strong positive association was found between alternative splicing and organism complexity (cell type number).
• This association was independent of gene content, protein length, proteome disorder, and protein interactivity.

Conclusions:

• Alternative splicing is a significant predictor of organism complexity.
• Transcript diversification via alternative splicing may determine a genome's functional information capacity.
• This study provides robust evidence for alternative splicing's role in eukaryotic evolution and complexity.