The new bond between Humans and Koalas
Gracen Schilling (12:00 Micro) found an article from Science Daily describing research from the University of Illinois on retroviruses from an unusual mammalian research system. Here is Gracen’s summary:
Scientists from the University of Illinois have found that koalas have a retrovirus that infects them, similar to the ones found in human genomes. Since 8% of our genomes derive from retroviruses, this new knowledge will give us the ability to understand our own viral lineage. The koala retrovirus (KoRV) was found in 39 different forms, all which are endogenous. Endogenous retroviruses are ones that are passed down from the one parent, or the other, to the baby. One endogenous KoRV was even found in both parents. The fact that koalas are the only other animal to transition from exogenous to an endogenous retrovirus gives us a way to understand how our own retrovirus evolved. Exogenous retroviruses are ones that infect a host, insert into to host cells genetic information, and then uses its hosts to create more viruses alike. The way a retrovirus becomes endogenous is when the exogenous retrovirus infects an egg or sperm cell, causing the viral genetic information to be passed to an offspring. Unlike humans however, the KoRV is in its beginning stages of development in koalas. However, this means we will be able to learn how to help the koalas deal with the retrovirus until it is no longer harmful. Over the thousands of years since the virus integrated with the koalas, it has been noted that they have suffered different physical effects. Just like us humans, the koalas will likely survive and adapt to the genetic changes going on despite the fact it is a long, slow and painful process. Once the retrovirus becomes part of the host, however, it will become more helpful than harmful, because the retrovirus will begin to help the host since it is the best way to ensure its own survival.
It is important to know that the likelihood of the thousands of KoRV’s in the koalas surviving is slim to none. Even though they found tens of thousands in the koalas, one hundred may survive. Most will disappear because some of the viruses are only present in one chromosome, so if it does not reproduce or is passed down than it disappears. The ones that are passed down are protected by the DNA repair mechanisms of the koala, so the reproduction of the viruses is very slow. Researchers estimated that the KoRVs were integrated into koalas less than 50,000 years ago. While this may seem like a long amount of time, it really is not considering some are millions of years old. Overall, this discovery is huge for us since it will show us not only how to help koalas to survive the retrovirus process, but by also allowing us to see how our retrovirus history originated.