Toward a resolution of the introns early/late debate: Only phase zero introns are correlated with the structure of ancient proteins
- 28 April 1998
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 95 (9) , 5094-5099
- https://doi.org/10.1073/pnas.95.9.5094
Abstract
We present evidence that a well defined subset of intron positions shows a non-random distribution in ancient genes. We analyze a database of ancient conserved regions drawn from GenBank 101 to retest two predictions of the theory that the first genes were constructed by exon shuffling. These predictions are that there should be an excess of symmetric exons (and sets of exons) flanked by introns of the same phase (positions within the codon) and that intron positions in ancient proteins should correlate with the boundaries of compact protein modules. Both these predictions are supported by the data, with considerable statistical force (P values < 0.0001). Intron positions correlate to modules of diameters around 21, 27, and 33 Å, and this correlation is due to phase zero introns. We suggest that 30–40% of present day intron positions in ancient genes correspond to phase zero introns originally present in the progenote, while almost all of the remaining intron positions correspond to introns added, or moved, appearing equally in all three intron phases. This proposal provides a resolution for many of the arguments of the introns-early/introns-late debate.Keywords
This publication has 14 references indexed in Scilit:
- Relationship between “proto-splice sites” and intron phases: Evidence from dicodon analysisProceedings of the National Academy of Sciences, 1998
- Origin of GenesProceedings of the National Academy of Sciences, 1997
- Exon/intron structure of aldehyde dehydrogenase genes supports the “ introns-late ” theoryProceedings of the National Academy of Sciences, 1997
- Intron positions correlate with module boundaries in ancient proteinsProceedings of the National Academy of Sciences, 1996
- Introns and gene evolutionGenes to Cells, 1996
- Intron phase correlations and the evolution of the intron/exon structure of genes.Proceedings of the National Academy of Sciences, 1995
- The recent origins of intronsCurrent Opinion in Genetics & Development, 1991
- Intron phylogeny: a new hypothesisTrends in Genetics, 1991
- The Exon Theory of GenesCold Spring Harbor Symposia on Quantitative Biology, 1987
- Genes in pieces: were they ever together?Nature, 1978