Population genetics and molecular evolution of DNA sequences in transposable elements. I. A simulation framework.

Area of Science:

• Population Genetics
• Molecular Evolution
• Genomics

Background:

• Transposable elements (TEs) are mobile DNA sequences with significant impacts on genome evolution.
• Understanding TE dynamics and molecular evolution is crucial for deciphering genome complexity.

Purpose of the Study:

• To develop a population genetic simulation framework to analyze TE behavior and molecular evolution.
• To investigate the influence of transposition, selection, and mutation on TE copy number and sequence evolution.

Main Methods:

• Developed a simulation framework incorporating random transposition/excision, selection against TEs, and mutation-driven activity loss.
• Analyzed the relationship between TE copy number dynamics and model parameters.
• Explored the molecular evolution of TE DNA sequences using simulated phylogenies.

Main Results:

• Weak selection maintains numerous, less active TEs; strong selection maintains fewer, highly active TEs with copy number fluctuations.
• Simulated TE sequences show active copies clustering and less active copies forming long branches, indicative of a star-shaped phylogeny.
• TE sequence phylogeny provides insights into TE evolutionary dynamics.

Conclusions:

• The developed simulation framework effectively models TE population genetics and molecular evolution.
• Selection strength is a key determinant of TE copy number and activity levels within a genome.
• TE sequence phylogenies offer valuable information for understanding the evolutionary history and dynamics of transposable elements.