Oldest Hominin DNA Ever Sequenced Challenges Tale of Human Origins

A 400,000-year-old DNA sample taken from a cave in northern Spain muddies science's ideas on the origins of humanity, introducing an entirely new set of problems and questions.

Unearthed at the site known as Sima de los Huesos, the DNA resembles that of an extinct branch of the human family tree known as the Denisovans.

Prior to the study published in the journal Nature, the record for the oldest human DNA ever obtained stretched back just 100,000 years.

According to co-author Matthias Meyer, a geneticist at the Max Planck Institute for Evolutionary Anthropology, the discovery "points to a complex pattern of evolution in the origins of [Neanderthals] and modern humans."

Sima de los Huesos represents the largest collection of hominin fossils dating to the Middle Pleistocene, a period stretching between 781,000-125,000 years ago. In all, the site has turned up at least 28 skeletons.

Previously, the fossils were classified as Homo heidelbergensis, an early human species that lived from roughly 700,000-200,000 years ago and the first early human species to move into colder climates and construct shelters.

Studying the skeleton's DNA was impossible, however, until Meyer and his team succeeded in developing the novel techniques that allowed them to both retrieve and sequence the highly degraded DNA.

Using bone powder from a skeleton's thigh, the researchers extracted its DNA and sequenced the genome of the mitochondria (mtDNA), comparing it to Neanderthals, Denisovans, modern humans and apes.