What are SNPs?
Find out what single nucleotide polymorphisms (SNPs) are and how they affect your health
The human body is made up of about 50 trillion individual cells, and in each of these cells is a nucleus containing the human chromosomes. A chromosome consists of a “very tightly wound thread”, the so-called DNA double helix.
DNA is the actual genetic code, i.e. the blueprint of the human body. This genetic code consists of about 3.2 billion letters in every human being and about 1% of this code represents the areas we call genes. A gene is an instruction for the body and usually has only one specific function. For example, there are genes whose function is to tell the body how to produce blue pigments, which then lead to blue eyes. There are also genes that tell the body how to break down food in the intestines to subsequently absorb the nutrients.
Unfortunately, our genes are not flawless and each of us carries certain genetic defects or gene variations that we have either inherited from our parents or that have formed by chance and now negatively affect our health. These gene variations occur very frequently and are usually just simple letter changes in the genetic code. The different variations weaken our immune system, increase our risk of heart attack or give us bad eyesight. Of course, each of us carries different variations, which means that some people have a higher risk of heart attack and others cannot tolerate lactose, for example. Diseases that are clustered in certain families are a good example of how an individual’s risk of disease can vary from family to family and from person to person.
These polymorphisms can affect our health, but in many cases they do not represent absolute facts of getting a disease, only an increased risk of disease. Whether the disease breaks out depends on external influences such as the environment and lifestyle. For example, if a person cannot tolerate lactose due to a genetic variation, that person is perfectly healthy as long as they do not drink milk. Complaints only arise when certain environmental influences occur – in this case lactose intake via food. It is the same with other diseases. For example, if an iron uptake regulation gene is defective, this increases the risk of iron storage disease and a precautionary lifestyle is needed to prevent the disease and perhaps prevent it altogether.
Experts estimate that each person carries about 2,000 genetic defects or gene variations, which in total affect their health and body and in some cases cause diseases. A variety of influences can cause changes in our genes (also called mutations), which in rare cases can have positive effects, but most often disrupt the function of the gene and negatively affect our health.
The most well-known cause of genetic defects in the media and Hollywood is radioactivity, whereby radioactive rays penetrate cells and damage our genetic code and thus, by chance, our genes.
Another cause of mutations and gene defects are certain substances such as carbon, which is found on burnt food. It also invades cells and damages our genes, which can lead to colon and some other cancers. The sun’s UV radiation also damages our genes and lead to diseases such as skin cancer.
The above influences can alter individual genes and disrupt their function throughout our lives, but we inherit the majority of our gene variations from our parents. Each embryo receives half of the father’s genes and half of the mother’s genes when the egg is fertilized, which together create a new human being with some of the characteristics of each parent. Unfortunately, genetic defects are also passed on with these genes, and so it happens that, for example, a polymorphism that causes heart attacks is passed from father to son and on to grandson, leading to the disease in each generation. However, whether the genetic defect is passed on is determined by chance and so some of the grandchildren may carry the genetic defect and others may not.
In this way, each person is unique and due to the accumulation and combination of the different genetic variations, each person has different inherited health weaknesses. With the latest technology, it is now finally possible to examine one’s own genes and read from them which very personal health risks exist. With this knowledge, preventive measures can then be taken and diseases prevented in many cases. This is the next step in preventive medicine and a new generation of health care.