Researchers around the globe are rewriting the history of human civilization, one ancient DNA at a time. From plague to smallpox, scientists are unearthing the origin of diseases that have shaped the narratives of our world over centuries. A BBC report on Monday shed light on how researchers discovered the reason behind ‘sudden deaths’ in Mexico in 16th century. The unknown pathogens have now been identified as hepatitis B virus. The scientists discovered this after extraction of ancient DNA from teeth of people buried at a chapel and hospital located in New Mexico. Previously, it was thought that the reason for outbreak had some European link. However, latest discovery showed that the human B19 parvovirus had African origin.
Elsewhere, smallpox is also getting new date of existence. Until recently, scientific proofs showed that existence of smallpox was confirmed with its presence in a 17th century mummy. Though many believed that it was present on Earth since 10,000BC, there was no credible evidence. This has changed now, courtesy new discoveries in paleomicrobiology. In 2020, a University of Cambridge scholar and her colleague extracted the smallpox virus from teeth of Viking skeletons. These were dated to AD600. In another instance, researchers found out variola virus in several locations that were known as trade hubs. These discoveries have pushed back the date of smallpox existence by over 1,000 years. According to the BBC report, the new studies have clearly proved that Vikings carried smallpox while travelling Europe and beyond.
Ancient-DNA analysis has provided insights into the origins of the plague, the BBC report further said. In a 2015 study that examined microbial DNA extracted from the dental remains of 101 skeletons, it was revealed that Yersinia pestis, the bacterium responsible for causing the plague, had been circulating among human populations for a minimum of 3,000 years before the first documented plague pandemic. Among the skeletons, the researchers identified Y. pestis DNA in seven individuals, with the oldest of these individuals having lived 5,783 years ago.
Another disease that has now got brand new narrative is syphilis. Earlier, the oft-cited viewpoint was that the 1495 outbreak of syphilis in Europe happened shortly after Christopher Columbus’ return from Americas. Since the outbreak was reported after Columbus’ trans-Atlantic trip, many believed that the disease spread from ‘New World’ to Europe. However, new analysis of ancient DNA shows a different picture. In 2020, a team of scientists extracted DNA from nine individuals, who had syphilis lesions on their bones. The ancient DNA were extracted from skeletons buried in cemeteries located in Estonia, the Netherlands and Finland. Carbon-dating confirmed that syphilis was very much present in Europe much before Columbus undertook his ambitious journey to Americas.
