Single Nucleotide Polymorphism - how gene variants make us unique

Every single person is unique - not only in a philosophical sense, but also in a genetic sense. The reason for the latter is that minimal differences in DNA have a great effect. Although we are 99.9 percent identical, the remaining 0.1 percent make us the genetic individual that we are. Responsible for this are, among other things, so-called single nucleotide polymorphism (SNP) - variations in our genetic interaction, which not only affect our appearance, but also our health.

Nutrigenetik Quelle: istock, AYDINOZON, 2018, Copyright: Scientific DX 2021

DNA - the blueprint of our body

To understand what single nucleotide polymorphism is and what it means, we need to delve a little into the biochemistry of DNA - the blueprint of our body: Every human carries 23 pairs of chromosomes with almost the same sequence of 3.4 billion DNA base pairs. Lined up like pearls on a necklace, the individual base pairs consist of different constellations of the four nucleic bases A (Adenine), G (Guanine), C (Cytosine) and T (Thymine). While in one person the nucleotide A is anchored at a certain position in the DNA section in DNA sequencing, in another person a G is located at this position. This variation of a single base pair (Nucleotide) at a certain position in the human genome (= totality of all genes in a set of chromosomes) is called single nucleotide polymorphism, in short SNP.

SNP Copyright: Scientific DX GmbH, 2020

The influence of SNPs on our health

The most obvious genetic variations within the genome relate to external characteristics, e.g. hair colour. However, most polymorphisms not only affect our appearance, but can be the origin of various diseases or predispositions, as the results of extensive genome-wide association studies have shown.

What SNPs have to do with a Caffè Latte

Other individual SNPs, on the other hand, have no discernible negative consequences for our organism, but may even be beneficial. One illustrative case is hereditary lactose intolerance, or rather lactose tolerance:

Lactose intolerance is a food intolerance (no allergy) to lactose. What many people do not know: Not tolerating milk in adulthood is the norm or the original genetic make-up of adults and affects 75 percent of the world's population. Infants and children usually have enough lactase digestive enzymes to break down the lactose so that they can easily digest breast milk. As we get older and have a different diet, the body no longer needs this enzyme and hardly produces it at all - hence the intolerance.

In our culture, where dairy farming has been practised for centuries, an SNP has become established in those elements of our genetic code that regulate lactase. This means that over 90 percent of people in Europe who can tolerate lactose have this gene variation and can enjoy caffè latte, yoghurt or curd cheese strudel without hesitation.


The young field of nutrition research in nutrigenetics analyses the effects of variations in the genome on nutritional and metabolic processes in the human body. The long-term goal of this branch of science is to derive individualised nutritional recommendations based on genetic principles. The findings of nutrigenetics are to be used for sustainable and healthy weight loss.


This article has been reviewed by unserem Medical-Team for accuracy of content.


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