What is DNA Testing and What Is It Used For?

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Whenever I hear about DNA testing, my thoughts immediately turn to Jurassic Park. You know at the beginning where Richard Attenborough is showing everyone how his scientists extracted DNA from mosquitos that had been fossilized, and used it to grow dinosaurs?

Anyway, that isn’t a real use of DNA testing – well, not that we know of anyway. Maybe there is an island lurking somewhere heaving with dinosaurs running about causing chaos!

What is DNA?

DNA is the very basics of what makes us. Every single cell in our bodies, from our blood to our hair, our heart to our skin, contains a complete set of our DNA.

DNA stands for deoxyribonucleic acid. It is a chemical made up of two long molecules. The molecules are arranged in a spiral, like a twisted ladder. This is called the double helix structure.

There is DNA in the nucleus of every cell. DNA carries genetic information. This contains all of the instructions that a living organism needs to grow.reproduce and function.

Genetic testing allows us to look at the DNA in close detail and the genes that we have inherited from our parents. Any mistakes (which are called mutations) in these genes can be identified through genetic testing and we can use that information to confirm the presence of a disease, or it can be used to take steps to prevent it in the future. There are stories of people having hysteroctemorys or masmectorys because genetic testing has shown that they carry a cancer gene and are at high risk of contracting the disease in the future.

Testing for mutations and disease isn’t the only reason for DNA tests. They can be used for other things, such as:

  • Parental testing – it can be used to identify if someone is the biological parent of a child.
  • Forensic testing – investigators and the police use testing to help to identify suspects or victims in a criminal investigation.
  • Genetic genealogy – to help people find out more about someone’s ancestry

We share 99.9% of our DNA with onther people, and it is that tiny 0.01% that makes us unique. These sequences are called genetic markers, and the only people with identical genetic markers are identical twins. However, you will share many genetic markers with your close relatives.

To carry out a DNA test, swabs will usually be taken from the inside of a cheek. Scientists then isolate the DNA and make copies, using a process called polymerase chain reaction, otherwise known as PCR.
PCR uses an enzyme that occurs naturally to copy a specific stretch of DNA over and over again.  The DNA molecules are then split at particular locations to separate them into ‘chunks’ and the code at those specific points is examined to create a DNA fingerprint. The fingerprint from two different samples are then compared to see if they match.

Occasionally, DNA testing can get it wrong, and when it does, there can be serious implications. They can be the only evidence is proving, or disproving whether someone is guilty of a crime, or whether someone is the biological parent of a child. Being wrong doesn’t happen very often, but when it does, boy, does it cause some problems!

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