DNA Explained: What Is DNA Testing & How Does It Work
Have you for a long time tried to find out more about yourself, your family, or even your ancestry? Well, DNA tests could just help you discover some of the things you never knew you had. All you need to do is spit in a tube and wait for a few weeks to get a report detailing the traits suggested by your DNA.
DNA in simple terms is a long molecule containing a person’s unique genetic code. It carries instructions for building the proteins that are essential for normal cell function, reproduction, and growth.
These genetic instructions are passed from parent to child. It is believed that half of a child’s DNA originates from the mother and the other half from the father.
With that out of the way:
DNA tests have quickly become a popular trend — from turning up lost relatives to finding relatives across the globe, from learning about your ancestry to identifying whether you face an elevated risk for getting certain diseases, etc.
In this detailed guide, we’ll provide new insights into DNA testing and the right test kits for you.
So let’s dive right in:
What Is DNA Testing?
DNA testing is a medical test that helps you learn about diseases you’re most likely to inherit, understand your ethnicity better, and identify potential relatives. It also identifies changes in genes, chromosomes, or proteins.
After the test, the results can confirm or exclude a suspected genetic condition. Also, they help determine whether there’s a chance of passing on or developing a genetic disorder.
As a result, over 1,000 DNA tests are currently in use, while a growing number of genetic tests are being developed.
Below are some of the methods that can be used for genetic testing:
- Chromosomal genetic tests: which analyze long lengths of DNA or whole chromosomes to identify large genetic changes. This can be an extra copy of chromosomes that is causing a genetic condition.
- Molecular genetic tests: these gene tests examine short lengths of DNA or single genes to establish if there’re mutations or variations that may cause a genetic disorder.
- Biochemical genetic tests: which analyze the activity level or the number of proteins. Present anomalies in either may affect the DNA and cause a genetic disorder.
Over the years, genetic testing amongst the general population has continued to grow in popularity, attracting everyone from moms-next-door to movie stars wanting to know about their origins.
Some top media companies are currently airing popular TV shows focusing on genealogy, showing celebrities’ reactions to discovering the truth about their family histories and roots.
DNA testing has now become a booming business. With different DNA testing available, some people are even doing the tests on their family pets.
Below are 3 common types of tests that can be done using DNA kits:
- Y-DNA testing: widely used for tracing paternal ancestry. This test can trace up to 100 generations.
- MtDNA testing: commonly used for tracing maternal ancestry. This test can trace up to 100 generations.
- Autosomal testing: here, pairs of chromosomes are used to identify the ethnic composition, distant relatives, or even medical risks that one is more vulnerable to. Unlike the other two, this test can only trace as far back as 8 generations.
What Are the Benefits of Genetic Testing?
Even though DNA testing is voluntary, it has potential benefits, limitations, and risks. Therefore, it is up to you to decide whether to take the test or not.
Geneticists and genetic counselors always provide individuals with information before they get tested. This allows people to know the advantages and disadvantages of taking the test.
They also let people know about the emotional and social aspects of testing.
Genetic testing will help you make better decisions about managing your health. It also eliminates doubt and suspicion in some cases, which provides a sense of relief. Positive results will provide a person with many options such as prevention, treatment, and monitoring among others.
Also, test results will guide a person to decide whether to have children or not. Newborn screening helps parents identify genetic disorders, giving them a chance to initiate treatment early.
What Are the Types of Genetic Tests?
DNA testing provides people with information about their genes and chromosomes.
Some of the most common types of genetic testing include:
Diagnostic Testing
It helps to identify or rule out a specific chromosomal or genetic condition. Testing confirms a diagnosis, especially when a certain condition is suspected depending on physical symptoms and signs.
Diagnostic testing can be done before a person is born or at any time during their life. However, this test is not available for all genetic conditions or genes.
Diagnostic testing will help you make informed decisions about your health care or managing the disorder.
Newborn Screening
This test is performed immediately after birth to identify if there’re any genetic disorders so that they can be treated early in life.
Newborn screening is done on millions of babies in the US every year. The infants are tested for congenital hypothyroidism, phenylketonuria, and other genetic disorders.
Prenatal Testing
This test is done to detect changes in a fetus’ chromosomes or genes before birth. Prenatal testing is performed during pregnancy to determine if a baby is at risk of having a chromosomal or genetic disorder.
Sometimes, performing this test can help couples make decisions about pregnancy or even lessen their uncertainty. However, prenatal testing cannot identify all possible inherited birth defects and disorders.
Carrier Testing
This test is done to establish if an individual is carrying one copy of a gene mutation — if they’re having two copies, there will be a genetic disorder.
Carrier testing is done on individuals in certain ethnic groups at risk of specific genetic conditions. It is also offered to people with a family history of a genetic disorder.
Both parents are tested to determine whether they’re at risk of having a baby with a genetic condition or not.
Preimplantation Testing
Preimplantation testing or preimplantation genetic diagnosis (PGD), is a specific technique that is performed to reduce the chances of having a child with a certain chromosomal or genetic disorder.
PGD is used to identify genetic changes in embryos, especially in-vitro fertilization or other assisted reproductive techniques.
During the test, a number of cells are taken from the embryos to be tested for particular genetic changes. Embryos that don’t have genetic changes are implanted in the uterus in order for pregnancy to happen.
Forensic Testing
In this test, the DNA sequence is used to identify the person in question for legal purposes. However, this type of testing is not used when detecting gene mutations linked to disease.
Forensic testing is used to identify catastrophe victims or crime, establish biological relations between individuals, and implicate or rule out a crime suspect, among others.
Predictive & Presymptomatic Testing
These tests help detect gene mutations linked to diseases that appear later in life after a child is born. Predictive and presymptomatic testing should be done on individuals from families who’ve got a known member with a genetic disorder.
Presymptomatic testing helps identify genetic mutations that can cause certain types of cancer. Predictive testing can identify if a person is at risk of developing hereditary hemochromatosis — even if they show no signs or symptoms at all.
Performing these tests will help you know if you’re at risk of developing a certain disease, and therefore, help you make your own health care decisions.
How DNA Testing Works
When doing a DNA test at home, you can just begin with a cheek swab or fill a tube with saliva, and then mail the sample to the company that is testing the DNA.
During the tests at the lab, the sample is analyzed and digitized. Algorithms are then used to identify common patterns. After the tests, the results will be sent to your personal email, including easily readable graphs and charts.
DNA sequencing lets scientists understand the order of the “letters” or nucleotides in a DNA molecule. These nucleotides or letters are the chemicals that make up the DNA. There’re only 4 letters: Guanine (G), Cytosine (c), Thymine (T), and Adenine (A).
Guanine only pairs with cytosine while thymine only pairs with adenine. Even though they may seem like a very limited alphabet, they contain genetic instructions that tell every cell in your body which molecules should be made.
These four letters line up within a long strand of DNA in an order that allows them to spell out genetic instructions. They contain plenty of space to accommodate long “words” whether in humans, dogs, or cats — and each string of DNA runs about 6 billion letters long.
Sequences are the portions of each strand while sequencing the genetic code is decoding the letters in a strand. The order of nucleotides in a gene will change from one person to the next, even though the instructions in the sequences produced may have similarities between all members of a species.
It is important to know that even though there’re many DNA testing companies, all tests are not created equal. The quality of the test results depends on the company you choose.
Below are the 3 main types of DNA tests:
1. The Whole Shebang (Mostly)
Even though the DNA testing companies doing the whole genome sequencing try to capture the 6 billion nucleotides in a genome, they may fail to capture every G, T, A, and C.
When DNA is packed together into chromosomes, it’s easy to miss a letter or word.
The whole-genome sequencing tries to capture the complete set of genes in an organism.
2. The Minimalist Approach
This test tries to look for single nucleotide polymorphisms (SNPs) and detects if there are single-letter misspellings sprinkled throughout the genome.
Scientists use SNP chips or SNP-array genotyping to identify collections of SNPs and grouped tests.
3. Focus On the Proteins
Even though DNA contains plenty of letters, not all of them mean something. Some sequences synthesize proteins, while others control the frequency of protein synthesis.
Other sequences provide instructions to molecules that are not proteins.
What Are Trace Regions?
Trace regions may show up on the test results, however, it’s a low confidence region. This means that you may or may not have ancestry from that region.
How To Compare DNA Tests
When looking for the best DNA test for you, you need to compare the tests above and choose the one that suits you best.
Below are factors that will help you compare your options:
- Affordability: Choose the DNA test that you’ll be more than willing to pay for.
- Analysis: choose a company that will provide the level of detail that you would like in your analysis. These may be written reports, interactive family trees, pie charts, etc.
- Features: You can choose Y-DNA, mtDNA, or autosomal testing — depending on whether you want to learn about possible medical risks, understand your ancestry, connect with potential relatives, or any other purpose of taking the test.
- Speed: Choose a DNA testing company that will give you the test results quickly.
What Is the Process for DNA Testing?
Many people would be curious to know how the process behind DNA testing works before they undergo a test. Genetic testing is a science and therefore, requires a lab and specialized equipment.
Below are some of the process of genetic testing:
Sample Collection
The most common sample collection system used consists of hair or bodily fluid from an individual. The least invasive DNA samples include blood and mouth swabs.
A mouth swab is collected by rubbing the inner lining of the person’s cheek using a swab stick.
Lyse Cells
In this process, an enzyme is added to a solution that contains the DNA sample to break down the membranes of the cells.
Separation
Even though there’re many ways of separating DNA, electrophoresis is the most common process.
Electrophoresis uses an electric field to sort DNA molecules in a sample provided — to separate the unique molecular structure of DNA from the rest of the sample.
Copying
PCR is used to produce copies of the DNA, which are then tested for genetic markers.
Testing
This process is used to identify genetic markers in the DNA to determine genetic relationships.
Since there’re thousands of genetic markers, the relationship testing reports on 16–21 particular genetic markers to prove whether there is a genetic relationship.
Matching
After obtaining the markers, they can then be matched against an unknown sample of DNA. This process is done to determine whether the unknown DNA sample is the same as the DNA donor.
During a paternity DNA test, the potential parent’s DNA is expected to match half of the child’s DNA markers. Half of a child’s genetic markers come from the mother, while the other half come from the father.
How DNA Testing Can Help You Plan a Healthier Diet
Choosing a healthier diet can be just as hard as sticking to one. However, with the help of DNA testing, you can be able to develop the best nutrition plan for yourself.
A healthy diet means giving your body all the nutrients it needs. This will help you stay on top of your fitness goals and keep your health in an optimal state.
Response to various foods, metabolic needs, diet-related diseases, and predisposition to obesity are all encoded in a person’s genes. Therefore, DNA reports will help you take a scientific approach and use it to your advantage.
You’ll also be able to choose personalized nutrition that will help you reach optimal health, well-being, and body image.
A reputable genetic testing company should be able to explore the weaknesses and strengths of your genes. The company should also provide you with easy-to-use DNA test kits, comprehensive reports, and accurate results.
Avoid one-size-fits-all dietary plans and stick to a personalized plan.
Below are DNA reports that will help you plan a healthier diet:
Nutrient Metabolism
Adequate intake of energy is required for vitamins, minerals, and proteins to be used effectively for their numerous metabolic functions.
It is believed that genes have the ability to regulate metabolic processes because they can influence the expression of hormones, receptors, enzymes, and other proteins.
A better understanding of how nutrients and genes interact could lead to improved pharmacological interventions and nutritional advice. This will help prevent or delay the onset of chronic illnesses and maintain lifelong health.
Advances in Nutrigenomics Research
Studies in nutritional areas have revealed breakthroughs for the field of nutrition and have begun exploring the association between human traits and genetic regions.
Nutrients can affect people depending on their personal genetic variations. Only a small number of people can be able to respond positively to particular nutritional interventions.
For example, people with variant PKU (phenylketonuria), should avoid foods rich in proteins including meat, milk, and dairy products — as they experience difficulties breaking down the amino acid phenylalanine. Persons with LCT genetic mutations should avoid dairy products as they have trouble digesting lactose.
Eating Behavior
Poor food choices contribute directly to obesity and weight problems. Eating behavior is a complicated interplay of psychological, social, physiological, and genetic factors that affect your food preference and eating behavior — meal frequency and quantity.
A study that was done by the Universities of Cambridge, London, and Oxford in 2017, identified that obesity is caused by fat mass and obesity-associated protein (FTO). Even though the FTO gene is located on chromosome 16, it is expressed in the hypothalamus, the pancreas, and adipocytes.
These regions are responsible for regulating appetite. When FTO down-regulates adipocyte production of leptin, it may contribute to obesity. Genetic variations in FTO may cause increased caloric intake, a consequence of obesity.
Food Intolerances
This involves the digestive tract’s sensitivity to certain foods and may cause symptoms such as diarrhea, intestinal gas, or pain in the abdomen.
Food sensitivity is associated with certain genetic variations and is subtle — a specific nutrient or ingredient may be causing you trouble and you may not even realize it.
Your DNA should be analyzed for variations linked to food intolerances. This way, you’ll be able to maintain a healthy eating lifestyle and reduce discomfort.
Final Thoughts on DNA Testing
DNA testing will help you reconnect with lost relatives, learn about your genetic make-up, identify whether you face an elevated risk of getting certain disorders, and more.
The best part is that you can buy most of these DNA testing kits with or without a doctor’s order.
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Disclaimer: This site offers health information and is intended for educational purposes only. This information does not replace professional medical advice, treatment, or diagnosis. In case you have any concerns or questions about your health, consult with a doctor, or any other healthcare professional. If you use the information provided on this site, it will be at your own risk.
