In Bacterial Natural Transformation by Highly Fragmented and Damaged DNA, researchers found that fragmented DNA is a nutrient source for microbes but not as potential substrate for bacterial evolution. The natural genetic exchange from dead organisms to contemporary bacterial can take place over hundreds of thousands of years.
The authors could only speculate about the implications to evolutionary theory. On one hand, it might be considered an additional source of genetic variation or mutation; a way for microbes to share beneficial mutations. On the other, any hopes for establishing a phylogeny, or determining the history of microbes, are compromised by microbes’ ability to incorporate DNA fragments of widely varying ages from very different organisms.
“The genetic process described here suggests that early horizontal genetic transfer could have occurred in primitive cells after uptake of short DNA segments, which would have augmented evolutionary change. In addition to its main function as an important nutrient source, short DNA fragments may have contributed to exchange of beneficial mutations in early cells and continue to do so in extant microbial populations.”
These findings, summarized on PhysOrg has implications for more than just evolution. Now even hospitals can not assume that sterilizing a room of live antibiotic-resistant bacterial confers protection, because new bacterial colonizing the room might find fragmented DNA containing resistance genes, take it up and become resistant themselves.
While PhysOrg tries to put a positive spin on the study, they do recognize this as a paradigm shift: “That DNA from dead organisms drives the evolution of living cells is in contradiction with common belief of what drives the evolution of life itself.”
It is too early to evaluate what this discovery may have on the battle between creationists and evolutionists. When lateral gene transfer was discovered in microbes a few years ago, evolutionists worried that the process could obscure phylogenetic studies, making it impossible to build the Darwinian ‘tree of life.’ This new discovery compounds the problem enormously.