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Oligonucleotide correlations between infector and host genomes hint at evolutionary relationships
Nucleic Acids Research
|May 25, 1990
Summary
Analyzing DNA oligonucleotide frequencies reveals strong correlations between humans and their viruses, and E. coli and its phages. This suggests evolutionary links can be inferred from these patterns.
Area of Science:
- Genomics
- Bioinformatics
- Evolutionary Biology
Background:
- Oligonucleotide frequencies in DNA can reflect genomic composition and evolutionary history.
- Previous studies have explored DNA sequence patterns, but comprehensive analysis across different organisms and their viruses is limited.
Purpose of the Study:
- To investigate the frequencies of oligonucleotides (3-6 base pairs) in human, human viral, E. coli, and E. coli phage DNA sequences.
- To compare observed oligonucleotide frequencies with expected frequencies using nucleotide composition and Markov chain models.
- To determine correlations between oligonucleotide frequency ratios across different biological sequence sets to infer evolutionary relationships.
Main Methods:
- Collected DNA sequences from GenBank for humans, human viruses, E. coli, and E. coli phages.
- Calculated observed (O) versus expected (E) frequencies for oligonucleotides of lengths 3-6.
- Employed nucleotide composition and Markov chain models (orders 1-3) to determine expected frequencies.
- Computed the O/E ratio for each oligonucleotide and calculated correlations between these ratios across different sequence datasets.
Main Results:
- Strong correlations were found between human DNA and human viral DNA sequences.
- Significant correlations were also observed between E. coli DNA and E. coli phage DNA sequences.
- Weaker correlations were noted between other organism pairs, though some correlation between viruses and phages emerged with higher-order Markov chains.
Conclusions:
- Oligonucleotide frequency analysis reveals distinct evolutionary relationships between hosts and their associated viruses/phages.
- These patterns suggest that parallel analysis of oligonucleotide series can help elucidate complex evolutionary connections beyond codon usage.
- The findings support the utility of genomic sequence analysis for understanding host-pathogen co-evolutionary dynamics.