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What is DNA?
September 29, 2017 / Mark A.
When you hear the term ‘DNA’ it’s likely that you get flashbacks to high school, sitting in a cold chemistry lab that smells suspiciously of gas, or a run-down classroom, staring at badly drawn diagrams on the board. Wherever your classes were held, your first memories of DNA are likely to be your lessons at school. However, we understand that it’s unlikely that you’ve come to this article with a full, extensive knowledge of DNA and everything that’s associated with it. If you have, welcome! But here we’re going to focus on giving you the lowdown of what DNA is, what happens when DNA doesn’t form quite according to plan, and just what we can use our knowledge of DNA for.
What Is A DNA Testing Kit?
DNA testing kits are, at their essence, pretty much what they say on the tin. A DNA testing kit – specifically a home testing kit – is a collection of materials that a person can use and then send off to be tested. These tests are a great way to test a range of different things, which we will get into a little bit later. All kits in different categories can come with a range of different equipment or requirements dependant on what they are testing for, though you’ll find that most tests will come with a cheek swab or a saliva sample, or may require a blood sample. In some special cases, DNA on household items can be used (an infidelity test, for example) but this is far less common. To truly understand what a DNA testing kit is comprised of and what it can do, you need to know what kind of test you’re looking for.
So, what is DNA?
Okay, so let’s start with the basics. DNA is a complex chemical found in chromosomes that carries genetic information about a person. The genes found in DNA are what make a person who they are – from their hair and eye colour, through to how their body functions. Genes are, in short, what we inherit from our parents, and ‘alleles’ are different forms of the same gene, which ultimately decide your characteristics.
Sound confusing? Let’s break this down.
Each cell in your body has a nucleus, which is the centre of a cell. In the nucleus, you’ll find the chromosomes, which are x-shaped formations. These chromosomes are essentially made up of long strands of deoxyribonucleic acid – or, to you and me, DNA! Each section of DNA will have a genetic code for making a particular protein, and these proteins are the aforementioned genes. Genes make up DNA, DNA makes up chromosomes, and chromosomes are found in the nucleus of a cell – simple. Mostly.
Now we battle structure. DNA is made up of repeating units that are called nucleotides – each nucleotide will contain a sugar and a phosphate molecule that make up the backbone of the DNA, alongside one of four organic bases. This organic base can be one of the following: adenine (A), guanine (G), cytosine (C) and thymine (T). The order of these within a single DNA molecule is completely unique to you, and is what then gives you your unique characteristics!
When DNA Goes Wrong
Unfortunately, our genetic codes don’t always go according to plan. In fact, in some cases, we can inherit diseases from our parents through our genes, even when our parents don’t appear to have the illness themselves – in this instance, your parents will be a carrier of a specific gene.
Remember the alleles we mentioned before? This is where these come into play. Different forms of the same gene are called alleles, and you’ll inherit two alleles for each gene – one from your mother, and one from your father. Think of eye colour – you’ll have one eye colour allele from your mother, and one from your father and it’s this combination that will determine yours! However, faulty alleles can cause countless problems, and here are just a few:
Cystic Fibrosis– those who suffer from Cystic Fibrosis have inherited two faulty genes from their parents, and the genetic disease manifests itself in physical symptoms. Those with Cystic Fibrosis will produce unusually thick mucus that is sticky, and it’ll even form in their lungs and airways. This causes their lungs to become congested, which leads to an increased risk of respiratory infections. Physiotherapy and antibiotics are used to fight infections and prevent and relieve congestion, but the disease can even affect the gut and pancreas, meaning food isn’t digested correctly either.
Autism – Autism, or rather the autism spectrum disorders (ASDs) are a group of developmental disorders. These can manifest and are characterised by impaired social interactions, problems in verbal and non-verbal communications and even repetitive behaviours or limited activity and interest. Autism can affect anyone, though it is statistically four times more likely to affect boys than girls.
Crohn’s Disease - Crohn’s disease is a chronic inflammatory disorder of the bowel, and while there is no known cause of the disease, it is known to run in families. In other words, if there is a history of this disease in your family, it could pass down to you.
Breast Cancer – Breast cancer is another disease that passes through families. However, the faulty alleles that make members of a family more likely to get breast cancer have been identified, and so it’s now possible to test people for this particular allele. If they have an increased risk, the patient can then make decisions as to what they want to do about the risk – whether that’s have surgery to remove breast tissue before any cancer can develop, or return to the doctor for regular checks.
Treatments for Disease
The treatment that we’re going to mention specifically in this case is gene therapy. This particular technique to treat and prevent illnesses is still experimental, but it’s been known to have lasting and amazing effects. In the future, this may be more widely used, and could allow doctors to insert genes into a patient’s cells to treat disorders rather than use medication or surgery. From replacing a mutated gene that is causing the disease, to ‘knocking out’ a mutated gene that isn’t functioning properly, gene therapy could be a promising treatment option.
However, this technique is still risky, and certainly needs some more research and refining. It is still being studied to make sure that it is completely safe and remains that way, but the tests are currently limited – so much so that it is only being tested on diseases that have no other cure. The introduction of genes into a patient’s body could mean cures for ‘incurable’ illnesses and mutations.
Forensics and Testing
DNA testing, whether as part of medical tests, the development of a family tree, or as part of forensic science, is something to be marvelled at – if only for the simple fact that it’s quite the show of scientific development.
Information about a person’s DNA in forensic science has been around since the late 1900’s, with genetic fingerprinting being introduced in 1985. Sir Alex Jeffreys at the University of Leicester introduced a process that used some of the small differences in DNA between different people to make a picture not unlike a barcode. The more DNA that is tested, the more different two fingerprints will be and the easier it may be to determine just who the DNA belongs to. Take this technology to a crime scene and it’s very useful at helping match the samples found at a crime scene, and those that are suspected of committing the crime or being there.
DNA testing doesn’t need to stay with crime fighting, however. Testing your DNA to find out your heritage or chances of a genetic disease is another development in DNA technology that has taken off in the last few years – particularly with the introduction of home DNA testing kits. These kits allow users to take their own DNA swabs, and from there they just have to send the swabs off to a company to have the DNA tested and analysed.
This kind of accessibility makes it easier than ever to confirm relation, parentage, and even help you find out your true heritage. Those keen social media users might remember a video passing around not too long ago by Momondo, involving participants who were so sure of their heritage – only to be proven completely wrong! By using DNA samples and comparing them to reference populations around the world, these companies can give their clients a better idea of just where their family comes from. While these are by no means 100% accurate, the accuracy is constantly improving with the more people that do these DNA tests – and the same can be said for other DNA tests too.
Family tree DNA tests are usually conducted by taking DNA and producing a ‘tree’ of potential matches. From here, the client will be given a collection of other trees of other users that match closest to theirs, and from there the client can match who they think fits their familial line the closest. DNA testing can then be used for confirmation, and voila. You’ll either have a match or you won’t.
In short, DNA is something to marvel and something to be thankful for. Not only does our DNA make up who we are and the characteristics that we possess, but it can tell us a lot about our health, and what diseases we might be prone to in the future. You can find out your heritage, your family history and even match DNA to find specific people if the need calls for it. As our understanding of DNA grows, so does the list of things that we can do with the technology and the knowledge that we have. From catching criminals to reuniting families, the world of DNA and genealogy is certainly one to watch.
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