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Short-range order in two eukaryotic genomes: relation to chromosome structure
1Department of Biochemistry Molecular Biology, Cell Biology, Northwestern University, Evanston, IL 60208-3500, USA.
Journal of Molecular Biology
|June 21, 1996
Summary
Fourier transforms reveal unique DNA dinucleotide periodicities in eukaryotic genomes, suggesting constraints from chromosome structure and new signals for nucleosome positioning.
Area of Science:
- Genomics
- Bioinformatics
- Structural Biology
Background:
- DNA sequence organization exhibits non-random patterns.
- Dinucleotide distributions can reveal underlying genomic structures.
- Nucleosome positioning is crucial for eukaryotic DNA packaging.
Purpose of the Study:
- To analyze DNA dinucleotide distributions in eukaryotic and prokaryotic genomes using Fourier transforms.
- To identify periodicities and deviations from random sequence expectations.
- To investigate the relationship between DNA sequence periodicities and genome organization, including nucleosome positioning.
Main Methods:
- Application of Fourier transform techniques to analyze DNA dinucleotide frequencies.
- Examination of periodicities ranging from 2 to 500 base pairs (bp).
- Comparison of sequence patterns between eukaryotic and prokaryotic genomes.
Main Results:
- Systematic deviations from random expectation were observed for specific dinucleotide steps across various periodicities.
- A distinct periodicity of approximately 10.2 bp was identified in eukaryotic genomes, linked to nucleosome positioning signals.
- This 10.2 bp signal was absent in prokaryotic genomes and strengthened in eukaryotes when analyzing "AA or TT" sequences.
Conclusions:
- Eukaryotic genome organization is significantly constrained by chromosome structure requirements.
- Novel signals related to nucleosome positioning were uncovered.
- The study reveals extensive non-random aspects of genome sequence organization beyond codon usage.