The term “ghost DNA” sounds rather eerie - but it actually stems from an amazing discovery!
Researchers have recently found evidence of a lost population of ancient creatures that were believed to have interbred with early West Africans about 50,000 years ago.
Scientists describe that the DNA of the “ghost population” was found in groups living in regions of Sierra Leone, Nigeria, and The Gambia.
This research helps us understand how archaic species created a genetically diverse population on the continent of Africa. Let’s learn more!
How Was The Study Conducted?
Did you know that the human genome contains your entire set of DNA and defines your characteristics and identity?
A team of scientists, led by computational biologist Sriram Sankararaman, used a statistical model to examine the genomes of 405 West Africans. The genomes were from the Yoruba and Mende groups - which contained from 2 to 19 percent of the ghost DNA. But first, let’s understand the difference between the “ghost DNA” and modern-human genetics.
Typically, modern species are characterized by DNA that was found in Homo sapiens. Modern humans’ genetics can sometimes be traced to Neanderthals and Denisovans, species of hominids (early humans).
When analyzing the genomes of West Africans, scientists marked certain parts of the DNA that did not appear to come from these modern species and compared it to modern human fossils. They realized that the sample did not come from Neanderthals or Denisovans, but from a species that may have not been discovered yet - hence the term “ghost DNA”.
This study provides evidence of a species that was previously not believed to exist. It also proves the existence of interbreeding in Northern Africa between different species of humans.
However, some questions are still left unanswered. Until scientists find physical evidence of the ghost species, it will be hard to formulate an identity for this newly discovered group.
Sankararaman and his team wonder if the genes are “just randomly floating in our genomes” or if they have any benefits. They also pondered if the ghost DNA came from one, or possibly even more, groups.
After this incredible discovery, scientists are hoping they can use the genomes to link unusual DNA found in other species to this unknown ghost population that existed tens of thousands of years ago. Who knows, maybe they will stumble upon another new species!
Sources: New York Times, NPR, Science News, BBC, USA Today, Phys.org