Genome Size Dynamics within Multiple Genera of Diploid Seed Plants

Abstract

Genome size in plant species is closely associated with many intracellular and environmental factors, which makes it important for adaptation and evolution. Although research on genome size changes has a long history, the problem continues to be challenging because many factors affecting this evolutionary process are still unknown. Despite substantial effort to investigate genome size changes in major plant lineages, the present-day picture remains rather static because the age of plant species is not always taken into consideration. We attempted to systematically investigate genome size dynamics in multiple genera of diploid seed plants. A remarkably strong intrageneric linear dependence between the genome size and evolutionary age of species was found. This linearity of intrageneric genome size dynamics has persisted over millions of years, suggesting gradual changes in DNA content unrelated to the natural selection process. Our results also reveal that some outlier species did not follow this general trend and could go through drastic changes in genome size over a short period of evolutionary time. We conclude that genome size within the genera of many diploid seed plant species is not stochastic and follows a linear dependence on the evolutionary age of the species.