What are SNPs?

One of the most important pieces of the genetic puzzle is a type of genetic variation/mutation called an SNP (single nucleotide polymorphism - pronounced 'snip').

SNPs are the most common type of inherited genetic variation among people. Each SNP represents a difference in a single DNA building block, called a nucleotide. For example, a SNP may replace the nucleotide cytosine (C) with the nucleotide thymine (T) in a certain stretch of DNA. Hence the name single nucleotide polymorphism. See the above diagram.

So far, around ten million SNPs have been identified in the human genome. 

Most SNPs have no effect on health or development.

Researchers have found some SNPs, however, that may help predict an individual’s response to certain drugs, susceptibility to environmental factors such as toxins, and risk of developing particular diseases.   

SNPs can also be used to track the inheritance of disease genes within families.  Source . 

Some SNPs bring weakness, but also some strengths. For example, in Ben Lynch's book 'Dirty Genes' he discusses how certain SNPs in an unhealthy environment can predispose us to cancer, but the same SNP in a healthy environment has a positive impact on personality traits - such as energy, enthusiasm and happiness. The environment you put your child in really does matter!

With the right environment, the positive can outweigh the negative, and the result doesn't have to be ill health. You are not held hostage by your genetics!

If you see certain patterns of ill health in a few generations, look not only at what the genetics is saying. Yes, there may be specific inherited mutations SNPs predisposing to certain diseases. But look at the lifestyle too. 

Did the son with an autoimmune condition drink heavily as the father did? Did the daughter with heart disease smoke, eat a diet full of sugar and live in a home full of mould just like the mother and her mother before her? 

The environment is SO crucial. It is not fair and not accurate to blame the 3 generations with heart disease on only genes. Usually, we see the same lifestyle running through generations of families. These inherited SNPs + the unhealthy lifestyle are what is causing the disease we see 'running' through families. 

It is important to understand that the impact that certain SNPs have on health is not definite. These are predispositions that are accelerated by the environment. 

Scientists also theorise that SNPs are evolutionarily necessary for the greater good of the community.

People with an SNP, for example, that causes the person to be highly sensitive to toxic exposures. These are the 'highly sensitive individuals' who are the 'lookouts' for the general population by feeling danger immediately by way of a reaction. Thereby saving many lives via warning the rest of the community about the poison/ toxin etc.