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 Understanding Genetics

What is the difference between
DNA and Genes?

DNA is the code of life. Our genes are made up of DNA (deoxyribonucleic acid) which is a self-replicating material present in nearly all living organisms and carries genetic instructions. These instructions act as ‘code’ for molecules in our bodies such as proteins.

The Human Genome Project estimated that humans have between 20,000 and 25,000 genes, more than 99% of which are the same in all of us. What makes us unique are alleles. Alleles, or genetic variants, are forms of the same gene with small differences in their sequence of DNA bases. It only takes a tiny change to one letter on the sequence to give a person a unique physical feature, for example anything from having blue eyes to the ability to metabolise different nutrients in your food.

The most common type of genetic variation is a single base change at a particular position, which is called a Single Nucleotide Polymorphism, or SNP for short. SNPs can lead to different forms of the same gene, or alleles. Some individuals have risk alleles meaning they have a higher risk of, say, a disease based only on their genetics.


What do the letters T, C, A and G?

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). The order of these bases form (or code for) different genes. Genes produce proteins which determine, maintain and build your unique characteristics. You can imagine bases being similar to letters of the alphabet appearing in a certain order to form words and sentences.


How are genes analysed?

Scientists keep track of genes by giving them unique names. As gene names can be long, genes are also assigned symbols, which are short combinations of letters (and sometimes numbers) that represent an abbreviated version of the gene name. You will see some of these on our genetic reports!

At Nell, we create panels of genes that relate to specific health, diet and lifestyle areas and look for SNPs. If we find one, or even two SNPs, we can help you understand the impact of these variants and how to adjust your diet and lifestyle with this extra knowledge about yourself.

We use a process called KASP to analyse your genetic sample, which is one of the world's leading genotyping technologies.

For more information on how KASP works click on this link.


Genes are only part of the story

It is important to remember in all these cases that DNA is only part of the story. Non-genetic factors, such as environment and lifestyle, are also important in determining your health and characteristics.

At Nell, we have science at the centre of our services. We constantly evaluate scientific evidence and only genetic predispositions that are supported by science are included in our analysis. We also avoid using absolute terms and instead, we explain your results in the context of possibilities, probabilities and relative risk.