DNA that is left in the remains of long-dead plants, animals, or humans allows a direct look into the history of evolution. So far, studies of this kind on ancestral members of our own species have been hampered by scientists' inability to distinguish the ancient DNA from modern-day human DNA contamination. Now, research by Svante Pbo from The Max-Planck Institute for Evolutionary Anthropology in Leipzig, published online on December 31st in Current Biology a Cell Press publication overcomes this hurdle and shows how it is possible to directly analyze DNA from a member of our own species who lived around 30,000 years ago.
DNA the hereditary material contained in the nuclei and mitochondria of all body cells is a hardy molecule and can persist, conditions permitting, for several tens of thousands of years. Such ancient DNA provides scientists with unique possibilities to directly glimpse into the genetic make-up of organisms that have long since vanished from the Earth. Using ancient DNA extracted from bones, the biology of extinct animals, such as mammoths, as well as of ancient humans, such as the Neanderthals, has been successfully studied in recent years.
The ancient DNA approach could not be easily applied to ancient members of our own species. This is because the ancient DNA fragments are multiplied with special molecular probes that target certain DNA sequences. These probes, however, cannot distinguish whether the DNA they recognize comes from the ancient human sample or was introduced much later, for instance by the archaeologists who handled the bones. Thus, conclusions about the genetic make-up of ancient humans of our own species were fraught with uncertainty.
Using the remains of humans that lived in Russia about 30,000 years ago, Pbo and his colleagues now make use of the latest DNA sequencing (i.e., reading the sequence of bases that make up the DNA strands) techniques to overcome this problem. These technique
|Contact: Cathleen Genova|