General, Research, Technology

What is a DNA test, how is it done and what is it for?

Since the structure was opened in 1953DNA, many methods have been developed that allow you to use this knowledge for a deeper study of how all living things on our planet function. All information about living things is encoded in the genes, and the carrier of all human or animal genes is DNA (deoxyribonucleic acid) - genetic material that contains the “life code”. In essence, DNA is a long molecule made up of building blocks - nucleotides. Nucleotides are denoted by the letters A, T, C and G, in DNA they appear in the form of letter pairs AT and CG. In the human genetic code, there are about 3 billion pairs of letters. But when did scientists learn how to conduct DNA tests and why are they needed?

Modern laboratory diagnostic methods allow you to identify many diseases at the earliest stages.

DNA molecule - what you need to know?

DNA in every human cell contains one and the samesame code, but each person has his own code. This is a unique DNA code by which you can identify the person himself and his children. We get our DNA code from our biological parents in equal amounts - 25% from each of the parents. The remaining 50% is our personal code. Therefore, siblings have a 50% match in DNA, which helps to easily determine this using the test.

In humans, most of the DNA is in the form of tightly folded strands called chromosomesthat are inside the nucleus of the cell. All cells in the body have the same DNA molecule.

Let me remind you that in a human cell contains 46chromosomes. If you try to unwind each chromosome and arrange it from beginning to end, the result will be a long double-stranded DNA helix about 3 meters long - and all this from one microscopic human cell. The DNA helix looks like a spiral staircase. "Steps" consist of four nucleotides: A (adenine), T (thymine), G (guanine) and C (cytosine). The location of these molecules is called the DNA sequence, which determines all the individual characteristics of the body. This is the genetic code in which it is written when, how many and which proteins will be produced in our body - from the formation in the form of an embryo to death. In fact, these are instructions that determine our physical characteristics and body functions. These instructions are contained in units called genes.

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Interesting facts about human DNA

  • The DNA of a person and a head of cabbage coincides by 50% (as if this is our sibling), but with DNA of a banana, we coincide by 60%. Amazing right?
  • Human DNA is 99% identical. Everything that distinguishes us (appearance, gender, voice, race, etc.) fits into just 1%
  • Human and chimpanzee DNA match 98%
  • About 2 grams of DNA could store all the information that is currently on the Internet
  • DNA breaks down in about 1.5 million years. Therefore, we are unlikely to succeed in cloning dinosaurs.

How and why do a DNA test?

Since DNA is contained in every cell of ourbody, studying genetic material - blood, skin, hair, saliva, etc. - using the principles of microbiology - scientists can find out the owner of a particular DNA. However, to obtain accurate results, experts advise donating blood from a vein. Today DNA analysis allows you to determine a hereditary predisposition to various diseasesrelatives have suffered or are sufferingperson. One of these diseases is schizophrenia - in my previous article I talked in detail about why this disease is so difficult to treat and study.

Moreover, by analyzing the DNA, specialists cantalk about what diseases a person may have in the future, determine individual intolerance to drugs, addiction to addiction and alcoholism, and much more.

All living organisms have DNA.

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The most common DNA test is polymerase chain reaction method or PCR. Today it is one of the newest andthe most accurate diagnostic methods. Despite the fact that this method is still considered experimental, it is widely and successfully used in medicine. So, the majority of tests for the presence / absence in the body of the new SARS-CoV-2 coronavirus, which are carried out all over the world, are PCR tests. The PCR method in 1993 was developed by the scientist Carey Mullis, who received the Nobel Prize for his discovery. The essence of the method is the use of special enzymes, which many times copy DNA fragments of pathogens (as, for example, with coronavirus) that can be found in samples of genetic material, for example, in blood. Then, experts verify the obtained fragments with the given base, which allows to identify the type of pathogen and its amount in the body.

The test itself is carried out in a special device - thermocycler, which cools and heats test tubes with samples of biomaterial. The accuracy of the result directly depends on the temperature regime.

It looks like an amplifier

However, the identification and determination of susceptibility to disease is not the only area in which resorting to the use of DNA tests. So, the appearance of DNA tests - as in due time fingerprinting (fingerprint detection method) - changedforensics. Thanks to DNA analysis, investigators have the opportunity to collect the criminal genetic material and catch it. But the most popular use of DNA tests is to determine paternity. Perhaps the fact is that this analysis allows you to get almost 100% result. Recently, my colleague Nikolai Khizhnyak in his article spoke in detail about the future possibilities of DNA research, I recommend reading it.

Summing up, I’ll note that today is a riddle of codeDNA has not yet been disclosed. We are at the very beginning of knowledge, what is it really? Having opened a small click of the door, we can only guess what prospects for the future may open for an understanding of what DNA is and how we can use this knowledge!