Evolution vs the number of gene copies per primitive cell

Area of Science:

• Evolutionary biology
• Systems biology
• Computational biology

Background:

• Accurate segregation mechanisms are crucial for modern cells.
• The role of gene copy number in early evolution is not fully understood.

Purpose of the Study:

• To investigate the impact of gene copy number on evolutionary dynamics in replicating systems.
• To explore the relationship between segregation mechanisms and the rate of advantageous mutant displacement.

Main Methods:

• Computer simulations were used to model gene replication and mutant displacement.
• The study analyzed systems with varying numbers of gene copies and segregation accuracy.

Main Results:

• Indefinitely large numbers of gene copies prevent Darwinian evolution by eliminating the genotype-phenotype link and growth advantage.
• Systems with fewer than 100 gene copies can still allow for advantageous mutant replacement.
• Multiple gene copies in primitive cells facilitated the conservation of less immediately useful genes, enabling future evolution.

Conclusions:

• Accurate segregation mechanisms and low gene copy numbers, as seen in modern prokaryotes, limit evolutionary potential compared to early systems.
• The evolution of accurate segregation mechanisms led to a loss of the ability to conserve and evolve diverse genes within a cell.