Genetically, to whom Romanians are related

Where we Europeans come from genetically

50 - 30 - 20. What sounds like a size specification, but actually describes us all. With "us" we mean the inhabitants of Central Europe and with 50, 30 and 20 percent our genetic composition, because it is a potpourri. Let's start from the beginning, i.e. with the oldest ancestors that can be found in our genetic make-up: the original Europeans, hunters and gatherers by profession.

They emigrated from Africa via Central Asia about 40,000 years ago and, when they arrived in Europe, they reproduced with the Neanderthals and ultimately displaced them. There are archaeological and paleoanthropological findings for this migration, but genetic studies also suggest it. 20 percent of our genes can be traced back to this group.

Another migratory movement influenced our genetic makeup 8,000 years ago. At that time, farmers from Anatolia immigrated, they now have 50 percent control of our DNA. "Half of today's genes in Central Europeans are actually Asian," says Johannes Krause, director of the Max Planck Institute for the History of Human History in Jena.

Asian components

An old acquaintance was also involved at the time: at least Ötzi's paternal line, according to the current state of science, is part of a basic genetic makeup that came to Europe from the Middle East at the time.

A migratory movement around 5,000 years ago was ultimately responsible for the last 30 percent of our current genetic makeup. The last arrivals were populations from the Russian steppe north of the Caspian Sea. "The expansion of this population has changed the genetic composition once again and brought with it another Asian component," says Krause.

We probably also owe the European languages ​​and our light skin color to this group. Because of this history of migration and the connection via the Bering Strait, according to Krause, the Europeans are genetically much more closely related to North and South Americans, also to Indians, than to the Chinese, for example.

Nice mix

So our genes are a mixture of different populations that have come to Europe over the past thousand years. "They actually mingled very well and did not stop at Great Britain or the Iberian Peninsula. With small exceptions such as Sardinia, the migratory flows have penetrated all parts of Europe," says Krause. "Because Europe is a very small region, there has always been a lot of genetic exchange." As a result of this mixing, all genes are represented everywhere, which means something like: We Europeans are all relatively closely related.

And yet: the composition of 50, 30 and 20 percent is not the same everywhere. "Depending on where you are, there are more or less components from the past, the mixtures differ," says Krause. How exactly our genetic data show where we come from was shown in a 2008 study by the University of California.

For this purpose, genetic extracts from Europeans and information on the origin of their grandparents were evaluated. When the researchers graphed their results along two axes, they received a map that was amazingly similar to the map of Europe - Italy, the Iberian Peninsula and even differences between Italian, German and French-speaking Switzerland could be seen on it.

The geographical origin of a person's ancestors can therefore be read from the genetic data. "From the mixture you know to a European that he is a European," says Krause.

Special specifics

In some regions the genetic characteristics are even particularly specific, for example in Sardinia. Krause: "Genetically, the Sardinians are almost completely composed like the early immigrants from Anatolia 8,000 years ago. There are hardly any hunter-gatherer or steppe genes."

This is what the investigation by the Californian researchers has shown: Due to the geographical isolation of Sardinia, there is a genetic population of its own, separated from the Italian mainland. The Estonians are also special. They have the largest amount of Ice Age DNA in Europe, the proportions of hunter-gatherers in the genome are very high.

And another country in Europe stands out when it comes to genes: Iceland, the "living laboratory", as Adam Rutherford calls it in his book "A Brief History of Everyone Who Has Ever Lived". A large number of Icelanders have made their genetic data available for research.

The company she owns is called DeCode Genetics and was bought by American biotech company Amgen in 2012. Together with the genealogical tables and kinship lines, which are preserved in Iceland almost up to the beginning of settlement in the year 900, it can be reconstructed how every Icelander is related to every Icelander. "That's great for a genetic study," says Krause.

Amgen is also enthusiastic: "With the Icelandic data, we can better understand the genetic basis of various diseases and thus find new therapies for them," says John Dunlop, Vice President of Neuroscience Research.

Patterns that lead to diseases in our biology, writes Rutherford, can often not be recognized in the individual, but can be seen in a large number of data. Since Icelanders are also isolated because of their geographical location, Rutherford says, it is possible to study "what is inherited and what is due to the environment".

Less genetic diversity

However, there are skeptics among scientists about research into new drugs using the Icelandic data. Johannes Krause is one of them. "Iceland is actually not the ideal population to conduct such research because the genetic diversity is much lower there." In order to be as representative as possible, says Krause, "such a study should be carried out where we come from, namely in Africa". Nevertheless, Krause also sees advantages: "In order to understand certain mechanisms, the project in Iceland is still very helpful for research."

However, Europeans differ genetically not only within, but also externally. For example when it comes to milk. Because half of Europeans are lactose intolerant, Krause knows: "It's written down in the genes." In Europe, however, 50 percent of people also have a mutation that has spread over the past 3,000 to 4,000 years and which makes it possible for us to drink milk in adulthood.

This unusual phenomenon is called lactase persistence, and according to Rutherford, selective DNA changes are responsible for it. "We are the mutants, in the rest of the world that is less common," says Krause.

Where caution comes from

And there is something else that distinguishes our genome: the traces of the plague that came to Europe with the steppe inhabitants 5,000 years ago. Those who survived responded with certain gene variants. Investigations of the genome of Roma in Romania, who once migrated to Europe from northwest India, and of those populations still living in India, have shown that the latter do not have these gene variants. So the plague has inscribed itself in the European genome.

Inscribed in our heads, we Europeans are also caution when it comes to genetic traits and assigning them to certain groups of people. "In the USA, patients in hospitals are required to state their ethnic origin, because with certain drugs you already know that they work differently depending on the migrant background," says Krause.

More and more closely related

In Europe, people are far more cautious when it comes to classifications, especially when it comes to terminology. The word "race" has been frowned upon since National Socialism, and people are now talking about ethnic groups or population groups. But now, precisely because of the research into the genetic make-up, it is again about differences and similarities - they are now becoming particularly clear.

Overall, says Krause, we are all increasingly related to one another. Due to the lively exchange and globalization, people in this world are moving closer and closer together - also genetically. (Bernadette Redl, CURE, August 22, 2018)