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The clinical importance of tandem exon duplication-derived substitutions

Laura Martinez Gomez1, Fernando Pozo1, Thomas A Walsh1,2

  • 1Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), C. Melchor Fernandez Almagro, 3, 28029 Madrid, Spain.

Nucleic Acids Research
|July 24, 2021
PubMed

Insights

Alternative protein isoforms from tandem exon duplications are rare but functionally vital. These ancient genetic events, present in over 90% of species studied, significantly impact human health and evolution.

Area of Science:

  • Genomics
  • Evolutionary Biology
  • Molecular Biology

Background:

  • Most human genes produce multiple protein isoforms via alternative splicing.
  • The functional significance of many alternative isoforms remains unclear.
  • Tandem exon duplication-derived substitutions represent a rare but functionally important class of alternative splicing events.

Purpose of the Study:

  • To catalogue tandem exon duplication-derived substitutions in the human genome.
  • To investigate the evolutionary origins and age of these events.
  • To assess the functional and clinical relevance of isoforms derived from these substitutions.

Main Methods:

  • Cataloguing 236 tandem exon duplication-derived substitutions from the GENCODE human reference set.
  • Phylogenetic analysis to determine evolutionary origins and age.
  • Comparison of clinical impact (pathogenic mutations) with other alternative splicing events.

Main Results:

  • Over 90% of tandem exon duplication events originated in teleost fish (at least 425 million years old).
  • Twenty-one events can be traced back to the Bilateria clade.
  • Isoforms from tandem exon duplications show significantly higher clinical impact, with >25 times more pathogenic mutations than other alternative isoforms.

Conclusions:

  • Tandem exon duplication-derived substitutions are ancient, conserved genetic mechanisms.
  • These events play critical roles in cellular function.
  • They have likely contributed significantly to metazoan evolution and human disease.

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