Poisoned inheritance of ancient genes

We will more or less like it, but this is certain: physiologically, we Spaniards are shorter, and Nordics are taller. The average height of OECD countries is 177 centimeters for men and 164 for women. In Spain we are slightly lower: 174 and 163 respectively. And although the size of the Iberian Peninsula has increased in recent decades thanks to economic development and improved social and sanitary conditions, there is an insurmountable element against which we can do little: genes dictate how far our heads will eventually leave the ground. And, in particular, the oldest genes that we carry.

A recent study published by the journal Nature found in the DNA of 5,000 human remains from more than 30,000 years ago clues to the physiological evolution of Europeans and, among them, the reasons for differences in height or, more importantly, from tendency to suffer from diseases such as multiple sclerosis or Alzheimer’s disease.

Researchers from the universities of Cambridge, Copenhagen and Berkeley have created the largest bank of ancient DNA in the world. By sequencing the genes of those people who lived in Europe and Asia millennia ago and comparing them with the DNA of modern Europeans, they were able to trace how these genes were dispersed and how the information they spread spread. they have physiological characteristics or susceptibility to disease.

The results may provide answers to some European genetic traits that have until now remained a mystery.

For example, it is known that the inhabitants of Northern Europe comprise a population with Highest incidence of multiple sclerosis on the planet. The study found that genes that significantly increase the risk of contracting the disease were introduced into northern European communities 5,000 years ago through interactions with human groups of hunter-gatherers from the East.

In fact, the reconstruction work allows us to trace how this genetic information was distributed over time. The communities carrying these MS genes belonged to the so-called Yamnaya culture, which settled more than 5,000 years ago in the Pontic steppe (between modern Ukraine, Russia and Kazakhstan). Interestingly, the same genes that carry susceptibility to multiple sclerosis also provide protection against infections caused by contact with livestock. Thus, these communities had a poisoned evolutionary advantage that they passed on to the northern Europeans with whom they hybridized. According to one of the study’s authors, Cambridge University professor Eske Willerslev, ““This discovery could change the way we think about the origins of multiple sclerosis and how it can be treated.”

Today, northern European countries have twice as many cases of this disease as southern countries. From a genetic point of view, the Yamnas may be the ancestors of northern Europeans and therefore the cause of this difference.

Intensive study of this impressive ancient gene bank has yielded other surprises. Among them are the reasons for morphological variability between different communities of Europeans.

The European continent was settled by modern humans through three waves of migration. Hunter-gatherers from Eurasia arrived in ancient Europe about 45,000 years ago. Later, around 10,000 BC, large numbers of settlers arrived from the Middle East, and a third influx of population occurred 5,000 years ago, in this case from the border between Eastern Europe and Asia. Anthropologists know that these migrations They gave rise to genetic exchange between new relatives and archaic populations settled on the continent. But this exchange was not uniform: differences in gene dispersion from one wave to the next are responsible for the physiological differences between northern and southern Europeans.

For example, people in Scandinavian countries are taller and have lighter skin than people in the Mediterranean because the former retain more genetic ancestry from the pastoral families who came from the Eurasian steppes.

But looks aren’t everything. Other genetic contributions have a greater impact on our lives than a few extra inches. Today in northeastern Europe, people are at greater risk of developing diabetes and Alzheimer’s disease. Because? The study suggests this is because they received more genes from the first migrations of hunters 45,000 years ago.

Likewise, it is known that we Europeans population with the lowest rates of lactose intolerance due to the fact that our genes combined with the genes of eastern agricultural societies that adapted to the consumption of milk 10,000 years ago.

A new study opens a window into the study of genetic variation from an unprecedented perspective. What is still known for sure is that DNA mutations cause biological changes that can affect a population’s ability to survive and adapt. But it is not yet entirely clear which of these changes determine the tendency to suffer from a particular disease: in other words, The genes that helped our ancestors survive today are a heavy burden that makes us victims of serious evil.

The now published work sheds some light on the genetic variance of neurodegenerative and autoimmune diseases, the origins of diseases such as autism, and why some communities are more prone to depression than others.