Self-Motivation
David Goggins
Former Navy Seal
Career Development
Bryan Cranston
Actor
Critical Thinking
Liv Boeree
International Poker Champion
Emotional Intelligence
Amaryllis Fox
Former CIA Clandestine Operative
Management
Chris Hadfield
Retired Canadian Astronaut & Author
Learn
from the world's big
thinkers
Start Learning

Oldest Known Early Human DNA Recovered

The more scientists discover about our prehistoric ancestors, the further they seem to fall down Alice's Rabbit Hole. Things just get curiouser and curiouser.

This post originally appeared on the Newton blog on RealClearScience. You can read the original here


As far as mountains go, the Atapuerca Mountains in Spain aren't much to look at. In many places, they amount simply to scrub-covered, limestone hills rather than towering, craggy heights. If the mighty Rockies of North America could speak, they might very well be scoffing.

But at Atapuerca, the focus is more on the sediments below the ground than the rocks above it. The area is home to a treasure trove of buried archaeological riches: fossils and tools belonging to the earliest known species of ancient humans. Rightfully so, the United Nations and the World Heritage Organization have designated the archaeological sites at Atapuerca as protected World Heritage Sites, for providing "an invaluable reserve of information about the physical nature and the way of life of the earliest human communities in Europe."

The most famous site at Atapuerca, Sima de los Huesos -- "The Pit of Bones" -- is precisely that. Located at the bottom of a 43-foot chimney in the winding cave system of Cueva Mayor, it contains approximately 5,500 ancient human bones dated at over 350,000 years old! Now, drawing upon this piled wealth of history, Matthias Meyer, a lead researcher at the Max Planck Institute for Evolutionary Anthropology, and a team of colleagues have recovered and analyzed the earliest known human DNA.

DNA, as you may very well know, is the molecular instruction manual for how to build life, and the DNA at Sima de los Huesos is thought to belong to Homo heidelbergensis, a group of extinct humans roughly comparable in height and looks to Neanderthals. Drilling into a femur present at the site, the team collected about two grams worth of bone, then isolated DNA using arecently discovered method that employs silica to make the process more efficient. The team focused on the DNA contained within mitochondria -- the powerhouses of cells -- which holds vastly fewer genes than does nuclear DNA, which is contained within cells' nuclei. Because mitochondrial DNA is passed down exclusively from mothers, there are usually no changes from parent to offspring. This makes it a powerful tool for tracking ancestry, which is precisely what the researchers used it for.

After sequencing 98% of the mitochondrial DNA genome, Meyer and his colleagues estimated the specimen's age using the length of the DNA branch as a proxy. The femur clocked in at around 400,000 years old, placing its former owner in the Middle Pleistocene and making the DNA by far and away oldest human DNA ever collected. The previous record belonged to 100,000-year-old Neanderthal DNA.

The team then attempted to determine the specimen's position in the ancient human family tree and were surprised to find that the owner did not share a common ancestor with Neanderthals, but instead with Denisovans, a mysterious subspecies of human discovered in 2008 that last shared an ancestor with Neanderthals and Homo sapiens about one million years ago. Indeed, the more scientists discover about our prehistoric ancestors, the further they seem to fall down Alice's Rabbit Hole. Things just get curiouser and curiouser.

Next up, Meyer plans to assemble nuclear DNA sequences from the specimens at the Pit of Bones in the hopes of learning even more about where they fit within the annals of human evolution. This will be a tall task, however. With a half-life of 521 years, DNA breaks down fairly rapidly even under the most optimal conditions: encased in glaciers or buried beneath arctic tundra, for example. Furthermore, with about 21,000 genes, human nuclear DNA presents a much more complex tome to completely piece together.

Source: Matthias Meyer et. al. "A mitochondrial genome sequence of a hominin from Sima de los Huesos." Nature. December 2013. doi:10.1038/nature12788

(Image: Javier Trueba, MADRID SCIENTIFIC FILMS)

Hints of the 4th dimension have been detected by physicists

What would it be like to experience the 4th dimension?

Two different experiments show hints of a 4th spatial dimension. Credit: Zilberberg Group / ETH Zürich
Technology & Innovation

Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.

Keep reading Show less

How often do vaccine trials hit paydirt?

Vaccines find more success in development than any other kind of drug, but have been relatively neglected in recent decades.

Pedro Vilela/Getty Images
Surprising Science

Vaccines are more likely to get through clinical trials than any other type of drug — but have been given relatively little pharmaceutical industry support during the last two decades, according to a new study by MIT scholars.

Keep reading Show less

Leadership, diversity and personal finance in the COVID-19 era

Sallie Krawcheck and Bob Kulhan will be talking money, jobs, and how the pandemic will disproportionally affect women's finances.

Politics & Current Affairs

Consumer advocacy groups are mostly funded by Big Pharma, according to new research

An article in Journal of Bioethical Inquiry raises questions about the goal of these advocacy groups.

Scroll down to load more…
Quantcast