What is the genetic identification of the person and why it is needed

What is the genetic identification of the person?

This definition of the genetic profile of a man, with the help of which you can see who owns the blood, saliva or other biological material, as well as to find out the degree of relationship between two people.

In the nucleus of every cell in the body has a helix of DNA, in which the genetic information is stored. You can imagine it as a huge statement, which will be built on the human body. DNA book is written with four letters, nucleotides. This organic compound consisting of carbohydrate deoxyribose, a phosphoric acid residue and the four variants nitrogenous bases: A (adenine), G (guanine), T (thymine) and C (cytosine).

Genome of all people identical to 99.9%. If we imagine that the instructions of DNA consists of 500 sheets, two different volumes will not match the text with just one page. Moreover, these variations are not concentrated in one place, but scattered throughout the book. They define the uniqueness of the person and allow us to find it among the billions of others.

And scientists are these differences?

Scientists do not look at the whole DNA of a book - it's a long, expensive and do not need to, because you need to find only a 0.1% difference. Instead, compare separate pages DNA - loci, which are the most common individual elements. Certain variant page is called an allele.

Most often analyzed microsatellite loci (short tandem repeats - STR). This DNA fragments with a repeating pattern of nucleotides, e.g. tgtgtgtgtg or aacaacaac. The nucleotide sequence is the same in all people, but the number of tg or aac and, accordingly, the locus length - different.

Going back to the analogy with the literature, we find that scientists know on what pages most often differences occur. They just look at the desired DNA fragments: comparing the same page from the book of the offender and the blood of the book at the crime scene, and draw conclusions.

But how to compare DNA fragments?

The procedure takes place in several stages.

1. Using the reagents from the sample of biological material isolated DNA. You can do this manually or automatically. A specific set of reagents depends on what kind of material you have: traces of blood, hair, semen, cigarette butts, or something else.

2. Estimate the quantity and quality of DNA in the material. To do this, use the special kit with a very sensitive PCR mixture (PCR - polymerase chain reaction). It allows you to determine whether there is a human DNA, it is sufficient for further research and how it is destroyed. After the reaction, the data analyzing computer program. If the DNA is too low or it is severely damaged, the laboratory will not be wasting reagents.

3. Carry out the polymerase chain reaction. With the help of reagents and different temperatures produce many copies of the desired loci - those pages, which should be a difference. This procedure is called amplification.

4. The genetic analyzer loaded dice with reproduction loci DNA, the device analyzes them and produces a file with the results. Now experts have the genetic profile of a man, and they can compare it with other results of DNA typing.

This is probably a very long time?

Previously, genetic identification really took a long time because there was only one way to find differences in DNA - restriction analysis.

Restriction enzymes cut the DNA helix into fragments. And not just anywhere, but only where there is a certain sequence of nucleotides. Different people have cut the length of the fragments will be different. Scientists compare them and determine how similar the test material.

For this method, you need a lot of good genetic material: fresh blood or tissue. Traces of a toothbrush, dried blood and even more old cadavers can be no question.

Today, due to the use of PCR for genetic identification need much less biomaterial, moreover, he does not have to be fresh.

In addition, equipment and reagents are constantly improving, making the process easier and faster still. Today, the results of genetic identification can be obtained within 8-12 hours after the filing of the material.

But where take these reagents and equipment?

Basically, reagents and equipment were purchased from the US and Germany or in the Russian distributors. In 2018 the company "Niarmedic" opened the first Russian production of kits for genetic identification, which is certified according to international standards.

In "Niarmedic" built its production, have developed their own reagents and passed certified according to international standards 9001: 2015Quality management systems - Requirements and ISO 18385Minimizing the risk of human DNA contamination in products used to collect, store and analyze biological material for forensic purposes - Requirements. In other words, the company delivers the same high-quality product, as well as foreign firms. In this case, sets entirely manufactured in Russia, the synthesis of all the components to packaging.

Now "Niarmedic" produces sets of reagents "Screening" to create databases and is preparing to release a set of "expert" for the analysis of biological material from crime scenes.

So that in the future identification procedure in Russia will become cheaper and can be used more often.

Where such methods are used?

Primarily in criminology. At the scene is collected samples that may contain DNA criminal, for example cigarette stubs, a drop of blood or hair. The material is then transported to the laboratory and determine the genetic profile.

When a suspect is apprehended, it will take a blood or saliva to analyze and determine the genetic profile. Compare it with that found at the crime scene, and with data from the public database, which contains information about the DNA of criminals.

In accordance with the Federal Law № 242-FZFederal Law "On State Genomic Registration in the Russian Federation" dated 03.12.2008 number 242-FZ (the latest version) in the base get genetic profiles of people who have committed grave and especially grave crimes, including rape and biological material found during the investigation, and profiles of unidentified corpses.

So, genetic identification need only forensic?

No, it is used in other areas.

Genetic research is helping biologists to analyze the origin of species, and anthropologists - to monitor the occurrence of populations. Historians can determine who owns the body of the burials. For example, DNA typing has helped identify the remains of the royal family were shot in a revolution.

Another field of application - the establishment of paternity. The genetic profile of the child's DNA is compared with the potential parent. It suffices to check about 19 pages loci to determine the degree of kinship with accuracyexamination of DNA to 99.999%.

DNA typing is also used in medical applications: e.g., bone marrow cells analyzed in transplantation.

Why use it more often?

Despite the mandatory collection of biological material at the crime scene, because of the high cost of DNA-typing procedure is conducted it is not always. The availability of reagents and equipment, the more chances to find the perpetrator.

In addition, now in Russia quite sparse database of genetic information, compared to the same Great Britain, where DNA fingerprinting runs every detainee, or the United States, where genetic information is all stored in the database military.

In the future, increased base will accelerate the detection of crime and the identification of bodies. So perhaps, in the future the list of groups subject to mandatory genomic registration will be expanded in Russia.