Wednesday, February 23, 2011

Virus-like Particles Speed Bacterial Evolution

Recent investigations into the rapid evolution of many strains of ocean bacteria have led to the identification of virus-like particles, called gene-transfer agents (GTAs).  These particles (vesicles) insert nucleic acid sequences into the bacterial genome at an alarming rate, increasing the rate of mutation (the genetic diversity and the evolution) of the bacteria they affect.

Studies of GTA structure reveal a protein-encased fragment of host genome. They reside in bacteria, but are easily spread to infect new bacteria and incorporate their genome into their new host.  Though they seem to exhibit similar infectious tendencies as viruses, “their only function seems to be transferring genes” (Eugene Koonin, National Institute of Health, Maryland).  In fact, they are such efficient means of gene transfer, that researchers at the NIH in Maryland have hypothesized that GTAs are largely responsible for the horizontal gene transfer in marine microbes.  Unlike viruses however (another major means of mutation), GTAs leave bacteria alive.  They have also proven to be much more promiscuous and efficacious than plasmid gene insertion. 

Jeffrey Townsend, an evolutionary biologist at Yale, explained that “in order to understand antibiotic resistance, pathogenicity, or the beneficial things that bacteria do for us, we need to understand how they evolve through horizontal gene transfer — knowing about this process can help us live in a world full of microbes." Further investigating the mechanisms of GTAs could help us gain a better understanding of microbe evolution and perhaps help us improve a whole host of medical treatments.


1 comment:

  1. I know it's not actually viral evolution, but I thought it was really interesting that the major means of aquatic microbial evolution was due to virus like particles.