A recent study proposes that the microscopic creature known as a Water Bear is able to survive extreme conditions due to how it uses the process known as horizontal gene transfer. Through this process, genetic material is able to move between both multi-cellular and unicellular organisms. Think of it like a ladder, the DNA can use the middle rungs to transfer over, rather than just having the linear pathway of the outside poles.
IS STEALING ALIEN DNA THE TRICK TO SURVIVING IN OUTER SPACE?
Essentially, the Water Bear or the Tardigrade is able to use the genetic material of other species it comes across in order to survive rather than using only the hereditary material that is transmitted at birth. According to the study, the Water Bear has collected “about 6,000 alien genes throughout its history, ” which means that the creature’s DNA is primarily foreign.
HOW DO WATER BEARS RECEIVE THE FOREIGN DNA THEY TAKE ON?
It is believed that the Water Bears live among other species like plants, fungi, bacteria and Archaea which are single-celled microorganisms. Thomas Boothby, a professor at the University of North Carolina, explains that genetic material can come from both direct ancestors and distantly related organisms. So instead of the Water Bears always using or having the direct DNA that is passed down to them from their parents, they are also able to take on DNA from distantly related species. The genetic DNA is spread out like a web rather than through a direct connection. By living alongside other species that are similar in cellular makeup, the Water Bears are able to take on parts of their DNA.
However, the University of Edinburgh believes that a lot of the horizontal genes that were transferred are actually genuine Water Bear genes and not foreign ones that were taken on from other species. The team of scientists has evidence that there are genes that have been transferred over from other types of bacteria, but that most of the genes that they believed came from other microbes are actually just contaminants. Nevertheless, even if there is evidence that some genes are authentic foreign DNA that has been transferred through the horizontal process, it provides insight into the evolution of microorganisms.
HOW DOES THE FOREIGN DNA GET CODED INTO THE WATER BEAR(S)?
If the Water Bear dries out completely, whether that be due to drought conditions or not being able to obtain sustenance, it fragments the DNA it has so that it can re-hydrate itself. By puncturing its own DNA and dividing it, it forces itself to take on new DNA such as proteins. When it does this, the fragments must heal, so any new DNA that has been brought in through the punctures is embedded into the newly healed cells. This is how scientists believe that the Water Bear can survive for so long without needing sustenance and how it can survive extreme conditions like outer space.