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Compositional compartmentalization and compositional patterns in the nuclear genomes of plants.
J Salinas1, G Matassi, L M Montero
1Departamento de Bioquimica, Instituto Nacional de Investigaciones Agrarias, Madrid, Spain.
Nucleic Acids Research
|May 25, 1988
Summary
Angiosperm nuclear genomes show compositional compartmentalization. Monocot genomes, particularly Gramineae, display distinct GC-rich patterns compared to dicots, impacting gene composition.
Area of Science:
- Genomics
- Molecular Biology
- Plant Science
Background:
- Nuclear genomes of angiosperms possess compositional compartmentalization and isochore structure.
- Significant variations exist in compositional patterns between monocots and dicots.
Purpose of the Study:
- To investigate compositional patterns in nuclear DNA of dicots and monocots (Gramineae).
- To analyze the compositional distribution of DNA molecules, coding sequences, and introns.
- To compare genomic compositional differences between monocots and dicots.
Main Methods:
- Analysis of nuclear DNA molecule compositional distribution (50-100 Kb size range) using density gradient centrifugation.
- Gene localization experiments in density gradient fractions.
- Examination of coding sequences (exons) and introns compositional distribution using GenBank and literature data.
Main Results:
- Dicots (pea, sunflower, tobacco) DNA molecules centered around 41% GC; monocots (maize, rice, wheat) centered around higher GC levels (45-48%).
- Vast regions (>100-200 Kb) surrounding genes exhibit remarkable compositional homogeneity.
- Monocot coding sequences show broad, asymmetrical GC distribution (60-70% GC), unlike narrow, symmetrical dicot sequences (46% GC).
Conclusions:
- Angiosperm nuclear genomes exhibit compositional compartmentalization and isochore structure.
- Gramineae (monocots) show distinct compositional patterns from dicots, particularly in coding sequences.
- Introns share compositional trends with exons but have lower GC levels.