The first thing that its versatility shows is that early mammalian genetic makeup was not as far from each other as thought before. Viruses are usually very specific to a host and a change in host usually means the end of that virus. The ERVs have also been able to exchange genetic material with other viruses making it evolve very quickly.
The genetic makeup of the ERVs is still present in modern viruses. Scientists discovered this by studying recent viruses and Strains from the ancient ancestor. However, viruses do not have fossils, and the scientist had to devise a new way to study their history. They did this by studying fossils of ancient mammals. From this, they could see traces of a change in genetic structure in areas viruses had attacked.
The challenge will now be to use ancient viral sequences for looking back in time, which may prove insightful for predicting the long-term consequences of newly emerging viral infections," said geneticist William Diehl. By studying the evolution of viruses,' scientists can perhaps be prepared to deal with pestering resistant viruses like the HIV. Perhaps tackle it before it evolves and destroys it using its ancient weaknesses.