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An oligopurine sequence bias occurs in eukaryotic viruses
1Department of Chemistry, Lehigh University, Bethlehem, PA 18015.
Nucleic Acids Research
|February 25, 1988
Summary
Viral DNA and RNA sequences show a higher frequency of long purine or pyrimidine strings than random chance. This pattern, observed in Epstein-Barr virus, mirrors higher eukaryotic DNA, unlike bacterial DNA.
Area of Science:
- Genomics
- Bioinformatics
- Molecular Biology
Background:
- Genomic sequences exhibit non-random patterns of nucleotide distribution.
- Understanding these patterns can provide insights into genome function and evolution.
Purpose of the Study:
- To investigate the occurrence and frequency of contiguous purine or pyrimidine strings in viral nucleotide sequences.
- To compare these patterns between different types of viruses and prokaryotic DNA.
Main Methods:
- Analysis of 24 DNA and RNA viral nucleotide sequences (over 346 kilobases).
- Examination of contiguous purine (e.g., A, G) or pyrimidine (e.g., C, T) residues.
- Statistical comparison against random base distribution models.
Main Results:
- Strings of ≥10 contiguous purines or pyrimidines were found 3.5 times more frequently than expected by chance in viral sequences.
- Epstein-Barr virus sequence analysis revealed an increasing bias for contiguous purines with string length.
- No overrepresentation of such strings was found in bacteriophage and E. coli DNA sequences.
Conclusions:
- Viral genomes, particularly those like Epstein-Barr virus, exhibit a significant bias towards long runs of identical nucleotides, similar to higher eukaryotes.
- This suggests potential functional or evolutionary significance for these repetitive elements in certain viral genomes.
- Prokaryotic DNA (bacteriophage, E. coli) does not show this bias, highlighting differences in genome organization.