Mirrored genome size distributions in monocot and dicot plants

Area of Science:

• Plant biology
• Genomics
• Evolutionary biology

Background:

• Genome size and chromosome number are fundamental characteristics of plant species.
• Understanding their variation is key to comprehending plant evolution and diversification.

Purpose of the Study:

• To analyze genome size and basic chromosome number variation across angiosperms.
• To investigate divergence patterns between monocots and dicots (eudicots) and between annual and perennial dicots.
• To identify constraints on genome size and chromosome number variation at different taxonomic levels.

Main Methods:

• Comparative analysis of genome size and basic chromosome number data.
• Nested analysis of variance to assess constraints on variation.
• Statistical correlation analysis.

Main Results:

• A clear divergence in genome size distributions was observed between monocots and dicots, and between annual and perennial dicots.
• Genome size divergence is more pronounced in species with larger genomes and across different taxonomic levels.
• Constraints on genome size variation are stronger and operate at lower taxonomic levels (family) in dicots compared to monocots (order).
• Variation in basic chromosome number is constrained at the order level in both monocots and dicots.
• Perennial plants exhibit higher basic chromosome numbers than annual plants.
• A negative correlation exists between genome size and basic chromosome number.

Conclusions:

• Genome size and chromosome number evolution differ significantly between major angiosperm lineages (monocots vs. dicots) and life history strategies (annual vs. perennial).
• Differential constraints on genome size variation contribute to observed divergence patterns.
• Higher chromosome numbers in perennials may facilitate genetic recombination for longer life cycles.
• A trade-off between genome size and chromosome number, potentially related to recombination mechanisms, is suggested.