Viruses and Genetic Occurences Specific to Koalas

In the article, “A Virus in Koala DNA Shows Evolution in Action”, the author is discussing the major discoveries that scientists have made on the different types of diseases and genetic occurrences that koalas are troubled by as well as how they can alter the course of evolution.

For starters koalas suffer from many diseases such as chlamydia, as well as cancers such as leukemia and lymphoma. The primary area of study is that if the koala retrovirus, or KoRV. This protein and genetic material associated with HIV. It is said that the viruses can go into the DNA of an animal and possibly change the overall course of evolution. These diseases can spread through genetics in the same way that genes do as well as transferred by a sort of viral infection. Retroviruses are made from RNA and when they infect the cell they translate themselves into DNA and then take over repeating the process. This process can make humans as well as other animals sick and when inserted into an egg or sperm cell it could become irreversible. When becoming part of the animal’s DNA it is called endogenous and will no longer have the infectious effect that it had before. This is now an extremely interesting topic in the scientific field. It’s even attracting the attention of scientists in different fields.

Originally this virus was thought to be junk DNA but now with further research it has become clear that some of these have changed the course of evolution. When researching different populations of koalas, they found the retrovirus in those that originate from Queensland. In a more southern they were believed to not have the virus. This is because most of the koalas in that region had been killed for the fur trade and the ones that survived were moved to small island, later to be reintroduced and even some have been killed to keep the population down. However, recently it was discovered that they did have the virus. The difference was that in these koalas the retrovirus was damaged. The beginning and end of the genetic code was there, but the middle was not. Some scientists believe that the missing middle is the reason for better health in these southern koalas.

There are scientists that believe that and experiment on this would be the answer to the many questions of this retrovirus. They would have cell lines for the retrovirus to grow in, insert a defective version of the DNA, and then examine if the full virus would infect them or not. A scientist named Dr. Theurkaut and colleagues focused their work on the bits of RNA called piRNA. This is what turns off the endogenous retroviruses and keeps them from replicating. This eventually takes part in how the viruses are disabled and can no longer cause disease. In some cases, koalas have a first-line genome defense involving this piRNA bits that respond to any virus inside of the genome. They then have a specific response for a particular virus that comes into play.

They want to test this by looking at different populations of koalas. It has also been found that koalas have an ancient retrovirus that has been dormant. It is possible that this new retrovirus may be activating these old viruses and causing complications. This could be evolution occurring in front of our eyes.