A new study revealed the complex patterns of migration by ice age humans based on the analysis of their bone samples.
While the extensive research may further define the history and origins of culture of Europe, it may also help shed light on the genetic pool of its people.
But to do this, we need to look at two very important points: Neanderthal DNA and the migration pattern itself.
A study published in Nature revealed that around 45,000 years ago, the first humans in Europe didn't just live with the Neanderthals, they also interbred with them, although most possibly very rarely.
However, over many years, the percentage of Neanderthal DNA present among Europeans has decreased significantly to only 2 percent. This points out that the earlier ancestors of Europeans may have possessed more of this Neanderthal DNA and that the substantial disappearance may be attributed to the the Neanderthal DNA's harmful effects to present-day Europeans.
Moreover, the DNA of the Neanderthals diminished over time because of natural selection. Nevertheless, the remaining 2 percent still seems to be quite substantial, which means Neanderthal DNA still has some undue influence on the European population not only with regard to health conditions but also on physical attributes such as light skin and straight hair.
Interestingly, the appearance of the early ice age Europeans suggests that they had darker skin and browner eyes than the Europeans today. Blue eyes appeared only around 14,000 years ago and pale skin sometime within the last 7,000 years. Both attributes were brought by farmers from the Near East.
Since limited interbreeding also happened between Neanderthals and early humans in the Middle East, is it possible that the reduction of Neanderthal DNA in the European lineage occurred not too long ago?
As mentioned, the first humans to arrive in Europe coexisted with Neanderthals, but about 30,000 years ago, the Neanderthals somehow vanished, with one theory suggesting that the presence of modern humans had a role in the disappearance.
Since then, different types of cultures seemed to have flourished, but it was assumed that these shifts in culture happened within the same population.
A comprehensive look at the genomes of the human bones of 51 people reveals otherwise - there was a wave of complex migrations, beginning with the Aurignacians followed by Gravettians and Magdalenians. Then about 14,000 years ago, farmers from the Near East also populated Europe.
Gravettians may have displaced Aurignacians, but it might not be on purpose. A plausible explanation is that the Gravettians were better equipped to deal with the frigid ice age conditions than the Aurignacians. In fact, the climate adaptation they developed not only allowed them to survive but also permitted them to grow their lineage in Europe. Only 10 percent of the European lineage can be attributed to the Aurignacians.
As for the Aurignacians, they were forced to retreat toward the west and south of Iberia including Spain. Their presence in the region may be corroborated by the introduction of the Magdalenians, who carried the genetic signature of Aurignacians and whose bone sample was found in a cave in Northern Spain.
In the end, we can say that the passing on of genes is very complex. Not only does it say so much about the different populations that have intermingled and lived within a particular area, but it also defines who the Europeans are right now - how they look like or what kinds of diseases they are susceptible to.