Almost 50 percent of the arthropod species are infected by a tiny virus called Wolbachia. Two scientists from Vanderbilt University studied Wolbachia's genome and found another set of DNA: the toxin produced by black widow spiders, which happened to be one of the hosts.
The hudband-and-wife team of Seth and Sarah Bordenstein discovered toxic DNA lurking within Wolbachia, a bacterium infecting spiders. Aside from its own genomes, the virus appears to be housing another gene for a black widow spider's venom and other animals' DNA - the bacteriophage or phage, WO. The study suggests that this transpired either because the other animals snagged the DNA from the virus or the virus stole this unknown genome from the hosts.
Is It Possible To Steal DNA?
Three domains comprise the tree of life - Eukaryota, Bacteria and Archaea.
Studies show that viruses can infect these three domains. Eukaryota consists of the most intricate life forms on Earth including plants, animals and fungi, whose cells only possess nuclei.
The remaining domains consist of the earliest life forms lacking nuclei and only having single-celled microbes. Bacteria and Archaea are composed of microorganisms thriving in severe environments like underground fuel deposits and hot springs.
Every virus infects only one of the three domains. Bacteriophages, for example, the viruses attacking only bacteria, cannot contaminate the eukaryotes or the cells with nuclei. This specificity made it possible for scientists to explore and use these "phages" in medical research to kill bacteria resistant to antibiotics.
It's not unusual for researchers to find evidence of gene swapping within virus DNA. But this new study signifies the very first time a virus seemingly borrowed, if not stole, the DNA of its victim. In layman's terms, the virus in question, WO, infects the Wolbachia bacteria that contaminate the bacterial bugs inside arthropods. No virus in history has ever been discovered to cross domains in the creatures it infects.
What's alarming is that one-third of the virus WO's genomes are seemingly mixing together with the arthropod kingdom instead of simply interacting with Wolbachia. In fact, WO was found to contain latrotoxin, the chemical in the venom of black widow spiders.
"There hasn't been another case of a latrotoxin being found outside of spiders," Seth Bordenstein told The Atlantic.
"Discovering DNA related to the black widow spider toxin gene came as a total surprise because it is the first time that a phage - a virus that infects bacteria - has been found carrying animal-like DNA," he said in a news release.
The scientists are continuously conducting further studies regarding this discovery. Their research is published in Nature Communications for those who want to check it out.
Photo: Matt Maves | Flickr
