What’s inside a raw DNA data file?
You may or may not know that if you’re a 23andMe or Ancestry.com customer, you can download your personal raw DNA data file. This is a simple file containing 600,000 genetic variations potentially found in your DNA.
What’s a genetic variation?
Genetic variation is a broad term for differences in your DNA. You may have heard that the DNA between two people is more than 99.9% identical. The differences in DNA that make up the difference between two individuals, is the genetic variation.
The most common type of genetic variation is a SNP.
SNP stands for single-nucleotide polymorphism. It is the simplest recognizable change in a gene.
Your DNA is made up of nucleotides, which are the basic building blocks your DNA. There are only 4 different kinds of nucleotides that make up DNA.
The word ‘polymorphism’ breaks down to its original Greek as changing shapes (poly – many, morph – change shape). So, a single nucleotide polymorphism (SNP) translated into understandable English simply means a change in a single building block of DNA.
Since our DNA is really the blueprint for our bodies (and to some degree our mind), SNPs - as small as they are, can have an impact on how our bodies work.
How do SNPs affect how our bodies work?
To dive deeper into the DNA as a blueprint analogy, most genes are blue prints for proteins. Proteins are the functional entities in our bodies. Proteins can be enzymes that break down the food we eat, they can be receptors – which are the locks to the keys that are the chemical messengers in our bodies(chemical messengers sch as hormones and neurotransmitters). Proteins can also serve structural function. From the collagen in your skin, to the muscle fibers and bones in your legs, all are primarily made of protein.
Hence, it easy to see that changes in the blueprint that is your DNA in the form of SNPs will result in structural and physiological differences (for example how well someone breaks down food, people’s height).
How do scientists use an SNPs to identify genetic traits?
The human genome contains over 20,000 genes made from approximately 3 billion nucleotides (basic building blocks of DNA)strung together, but the variation within people is relatively low. Within a gene, most of the millions of nucleotides can be the same. But, a single nucleotide of a difference can change the function of the resulting protein.
Through designing clever experiments, scientists have been able to determine which SNP locations are sites of genetic variants and how these variants affect different traits. In fact, most direct-to-consumer DNA testing companies rely on SNP testing to analyze your DNA and report on your traits.
Only looking at the best studied SNPs, allows direct-to-consumer companies to test a much smaller number of locations within the DNA (and not the entire 3 billion!). This significantly decreases the costs of genetic testing. Most genetic testing companies test upwards of 600,000 SNP locations in a variety of genes, which gives them an idea of which gene variants you have inherited that affect a variety of health, disease, physiological, and cognitive traits.
Interestingly, the companies that analyze your DNA for these 600,000 genetic variants don’t actually interpret and tell you about all of that information! There’s just too much there to interpret. Imagine reading through 600,000 pages trying to figure out what it all means. Luckily, they do allow you to download your raw DNA data. The ability to download your raw DNA data allows for you to learn more about yourself.
By downloading your raw DNA data, you can use it to upload to other services that are able to interpret more of the 600,000 genetic variations found in the raw DNA data file.
For example, at GENEius, since neuroscience and the brain is our specialty, we focus on interpreting genetic variations that have been scientifically found to associate with various cognitive traits. Other companies are able to interpret other genetic variants and tell you about other things such a diet, exercise and so on.