Ancient Human DNA Suggests Twisted Roots at Base of Human Family Tree
Scientists have sequenced DNA from the 400,000-year-old remains of an early human found in the Sima de Los Huesos cave in Spain. It not only shatters the record for the oldest human DNA sequence ever obtained, but is also forcing scientists to question what we thought we knew about human origins.
Traditionally, scientists have compared the measurements and proportions of these skeletons in order to place our ancestors along the human family tree and evolutionary timeline. The skeleton up top, from the Spanish cave, is classified as Homo heidelbergensis, a group of human relatives from Europe who, according to the bones, are thought to be the ancestors of Neanderthals.
But new and powerful DNA sequencing technology has given us the ability to stitch together sequences from older and more degraded DNA samples than we ever thought possible (I wrote about a 700,000-year-old horse sequence earlier this year for WIRED). The sequences in the Los Huesos DNA don’t agree with the old bone story.
The sequence shows that this 400,000-year-old DNA is most related to Denisovans, a group of early humans previously only found in Siberia (AKA “not near Spain”). It was also related to Neanderthals, which fits with the old idea, but suggests that there was a lot of interbreeding and migration going on in these groups, even before modern Homo sapiens had left Africa.
The genomic revolution is changing a lot about science, and the study of human origins is one of the fastest evolving (pun intended). This new info has confused the hell out of scientists, frankly, and there’s a lot of work to be done.
To find out more, head over and read Carl Zimmer’s detailed breakdown at the New York Times, and his accompanying blog post that explains a lot about the techniques they used.
The roots of our family tree tell a twisted and gnarled tale, written in fragmented sentences, but modern technology is beginning to bring those lost words to light. Hopefully they aren’t jibberish.