Researchers at Bigelow Laboratory for Ocean Sciences (East Boothbay, Maine, USA) have recently quantified a remarkable evolutionary process: a typical marine microorganism acquires and retains approximately 13% of its genes per million years through horizontal (lateral) gene transfer. This rate corresponds to roughly 250 genes exchanged and retained per litre of seawater each day
These transferred genes include those that provide either a selective advantage or are sufficiently neutral to persist via genetic drift—both well-established mechanisms of evolutionary change.
Some creationist arguments misapply Shannon Information Theory, claiming that gaining new genetic information violates the laws of thermodynamics. However, such arguments disregard key biological realities: cells are open systems capable of energy and material exchange; genome duplication and horizontal transfer are well-documented evolutionary processes; and substituting one nucleic acid for another does not create matter ex nihilo - facts of which any qualified biological scientists should be aware.
Furthermore, the successful retention and spread of horizontally acquired genes within microbial genomes provide clear, empirical evidence of Darwinian evolution in action. Although Charles Darwin formulated his theory without the concept of genes — speaking instead of 'heritable traits' — his mechanism of natural selection precisely explains how heritable variations can spread through populations over time.
This study also highlights that microorganisms can evolve not only through mutation and selection but also by acquiring pre-adapted genes from their environment, often from distantly related organisms. Consequently, these newly acquired genes can propagate rapidly within the recipient lineage.
The findings further challenge traditional microbial taxonomy, blurring species boundaries at the genetic level: horizontally transferred genes may function just as effectively in their new hosts as they did in their original genomes, thanks to the universality of underlying molecular machinery (e.g., replication and translation systems).
