A femur discovered in a cave in southwestern Germany has provided researchers with firm evidence that a small population of humans left Africa and then vanished, long before the big migration that saw humans populate the globe. Signs of this mysterious early migration remained in the DNA of the Neanderthal who left the leg bone behind, revealing not only a previous tryst between the two hominin populations, but a sign that Neanderthals were far more diverse than we thought. A team of scientists led by the Max Planck Institute for the Science of Human History and the University of Tübingen in Germany used the DNA from the femur’s mitochondria to determine its relationship with other Neanderthals and modern humans.
Neanderthal and human history is a little complicated. So stick with us.
Neanderthals and humans are regarded as close cousins, either under the same species of Homo sapiens or a closely related species Homo neanderthalis.
Mitochondria – our cells batteries – contain a set of genes separate from the DNA bunched up inside our nucleus. Since mitochondrial DNA mutates in a fairly predictable, conserved fashion, we can measure and map its mutations to get a good idea of when two populations last shared them. Differences between our mitochondrial genes suggest we last shared a common ancestor a little over 400,000 years ago, though previous studies on nuclear DNA had estimated a split as far back as nearly 800,000 years ago.Another group of human cousins dubbed the Denisovans also split off from a group of Neanderthals roughly 400,000 to 450,000 years ago before they went wandering the Earth.
The thing to note is Denisovans have nuclear DNA that matches Neanderthals’ DNA more than our own. Which makes sense, since Denisovans probably split off from a Neanderthal population.But Neanderthals and modern humans have more similar mitochondria. More here: New DNA from a Neanderthal bone holds evidence of a lost tribe of humans