DNA defines us

Genetics decide How our DNA determines our life

Tinker with the genes a little and the result is the "super baby"! Imagine if the development of a child were no longer left to evolutionary processes or even to chance, but were based on clear guidelines. The result would be people with improved skills, perfectly aligned with their professional or artistic careers. Is that a realistic vision of the future or just science fiction stuff?

Only one percent makes the difference

For the "perfect" baby, one must first of all have understood our complete and, above all, complex genetic make-up. And we're still a long way from that, says Professor Rami Jamra, human geneticist at the Leipzig University Hospital: "What we know is that DNA is relatively long, that's around 2,000 books of 500 pages each."

Scientists assume that almost everything that distinguishes us from one another is made up of just one percent of DNA: size, eye color, hair color and intelligence, but also the risk of developing certain diseases. But how exactly does it work? In simple terms, you can think of DNA as a long thread with billions of letters strung together. Actually, the order of these letters is fixed. However, if you compare the DNA of two people, there are always places where the letter differs.

Complex diseases difficult to decipher

needle in a haystack

If one imagines the identification of such gene combinations and their effects in the context of the entire DNA, the search for a needle in a haystack seems like child's play. However, the genetically complex things are precisely the ones that really count, explains Jamra: "Heart disease, readiness for cancer, that is, the majority of our diseases, has a large genetic component and none of them have been clarified. I think we need time and a few bigger machines, but will that be 100 percent deciphered? At least not in the next few years. "

Heredity studies are essential

In order to understand which sections of our DNA are responsible for what and in which combinations they produce certain properties, scientists would have to analyze the genes of many people and then compare them with the manifestations of certain characteristics. But since this is very time-consuming and expensive, one works a lot with findings from heritable, so-called heritability studies.

Jamra gives the example of identical twins: "If one twin has the property A, what is the probability that the second twin also has this property A? And that can be done in larger cohorts. And if the probability is 100 percent, then the heritability (the measure of the heritability of traits) is, to put it simply, 100 percent. That means, this trait A is 100 percent genetically determined. But if the other twin has this trait just as randomly as everyone else in the normal population, then the heritability is 0. Genetics has nothing to do with it, because twins are almost a genetic copy of each other. "

"Unbelievably determinative genetics"

In such cases, however, the researchers only know that the trait or disease is genetic. It is therefore still far from clear to what percentage or which section of the DNA is responsible. Jamra is certain, however: "There is practically nothing that is not heritable. Even accidents are heritable - at least in part. Genetics are incredibly decisive."

I beg your pardon? What does DNA have to do with accidents or mishaps? Jamra believes that every decision we make has its roots in our genes - including how attentive and willing to take risks we drive. How great the genetic influence is in each case cannot be precisely determined.

Genes and environmental influences

Because in the end it all boils down to the question of what influence genes and environmental influences have on these processes. But even this question cannot be answered simply because the two factors cannot be clearly separated from one another. They are mutually dependent. For example, anyone with a high level of musical intelligence enjoys learning to play an instrument as a child and goes to concerts more often and is given more support. Both areas influence each other.

Turn genes on and off

Some genes can even be deactivated or activated by environmental influences. When we come back to the book comparison, it's not just about the text that is in our DNA, but also about the emphasis. We determine it with our lifestyle: The letters stay the same, but it sounds different - and sometimes it has a different meaning. Admit it is complicated. And our genes are still a book with seven seals in many areas. But science is working to not only understand them more precisely, but also to change them for the better.

The question still remains, when will the first "super babies" with the genetically modified superpowers be born? Professor Jamra remains cautious about the answer, at least as far as time is concerned. "Well, I think it will come sometime, but not soon."