We talk about how a DNA paternity test is performed. Today, this is the only way to determine with 100% certainty whether the alleged father is the biological (natural) father. Just 5 years ago, DNA paternity testing was carried out mainly by court decision (in the event that a man refused to pay alimony, arguing that his wife was potentially unfaithful).
Recently, more and more men want to do a DNA test in order to make sure that they are raising their child. This is due to the fact that, according to scientists, approximately every 13 man in the world is raising someone else’s child.
Therefore, in developed countries, a DNA paternity test has long been called the “test of paternal peace of mind.”
Threads to the past
The genetic laboratory "Medical Genomics" in Tver is one of the largest in the country. Every day dozens of envelopes with biological samples from all over Russia and the CIS countries arrive here. Experts establish relationships between fathers and children, brothers and sisters, grandmothers and grandchildren. Relationships between people can be established in just a few hours. “If you need to establish a relationship, for example, between a grandfather and a grandson, then one of the approaches is a Y-chromosome analysis,” explains the head of the laboratory, Vladislav Zavarin . — It is transmitted exclusively through the male line. The paternal grandfather and grandson will be fully compatible. Mitochondrial DNA is passed down through the female line. Thus, it is possible to establish kinship directly even after several generations.”
This is what the smear envelope looks like. Photo: AiF / Yana Khvatova
Mitochondrial DNA is best preserved in bones and hair. This allows us to analyze the remains of a person who lived a thousand years ago and find his relatives in modern times. Based on the analysis, it will be possible to determine which ethnic group the person belonged to and create an approximate sketch of him. Cornelia Mango came to us ,” says commercial director of the laboratory Daria Popova . — We did an ethnicity test for her. She has blood mixed from different parts of the world. In such cases, you can determine the approximate appearance of a person: cheekbones, nose. You can also find out in which country a person’s genes originated, what ethnic group his ancestors belonged to.”
A laboratory technician takes a swab from the customer’s cheek. Photo: AiF / Yana Khvatova
DNA test: is it worth paying?
With the development of science, methods have emerged that greatly simplify the determination of kinship. The DNA test in this case is one of the most popular, but not the cheapest. The cost of a standard analysis reaches 10–40 thousand rubles. The final price depends on the urgency and other nuances. If the test is ordered by the court, it is paid for from the budget.
If the test is done while the woman is still pregnant (this procedure is quite dangerous for the fetus), then the cost of the analysis doubles. However, many fathers are willing to spend money to finally find out their relationship with their child.
It is known that during the analysis, a specialist compares the set of genes of a minor with the genes of the intended parent. For the determination, biological material from both subjects is taken (usually saliva or hair, but there may be blood or skin particles). If the result is positive, the analysis shows 99.9% probable similarity. A 100% guarantee is not given, but this is quite enough.
The good thing about a DNA test is that even if a parent dies, paternity can be established. For example, compare the genes of a child and the closest relatives of the deceased. Such an analysis will be accepted in court without any problems.
How is DNA analysis done?
Different people come to the laboratory. These are men who doubt the fidelity of their wives, grandmothers who suspect that their daughter-in-law is cheating on their son, women who want to obtain alimony from their husbands. Wealthy people often turn to us and are attacked by “golddigers”—girls who claim to have a child with a famous or rich man.
The specialist cuts off some of the cotton wool from the stick. Photo: AiF / Yana Khvatova
As a rule, a DNA analysis in a laboratory is completed in two days, but if necessary, it can be completed in a few hours. It all starts with the fact that in different cities of Russia, people who contact the laboratory have a scraping taken from the inside of their cheek using a special cotton swab. Many people mistakenly believe that geneticists take saliva for research, but in fact, specialists only need epithelial cells of the oral mucosa. Often people do this scraping themselves, at home, and then send the sample to the laboratory. “There were funny cases,” Daria smiles, “people brought a whole bag of chewing gum, cigarette butts, collars, hair from a comb, nails. We told them: “Why didn’t you call us before bringing this?”
DNA samples travel through the premises through a transfer window. Photo: AiF / Yana Khvatova
The scraping is done with two cotton swabs so that a repeat analysis can be carried out if necessary. It doesn't hurt at all and takes 1-2 minutes. The sticks are sealed in a special envelope on which the client’s first and last name, age and race are indicated. After this, the envelope is sent to the laboratory in Tver. Here, samples are registered, assigning each an individual number, and all information is entered into a database. Then the analysis itself begins.
A small box in the hands of the head of the laboratory is the DNA preparation. Photo: AiF / Yana Khvatova
The laboratory technician cuts the cotton tip off the swab into a sterile tube and adds a special reagent that allows DNA to be extracted from the sample. The resulting solution is brought almost to a boil in a microcentrifuge. After this, the tubes are transferred to the next room, where they are subjected to PCR - polymerase chain reaction. Bacteria and viruses can be found using this method. The laboratory is completely sterile. The test tubes enter the PCR area through a small transfer window so that employees do not go out into the corridor with the solution. Employees wear full-body gowns and caps. Laboratory assistants perform all manipulations wearing rubber gloves. All these measures are necessary to eliminate the possibility of sample contamination.
All work areas are illuminated with ultraviolet light. Photo: AiF / Yana Khvatova
How to eat to always be in shape
General recommendations for a healthy diet are about the same: more vegetables and protein, less sugar and saturated fat. Such a diet will not harm your health, but how effective it will be depends on your genetic predisposition.
People with an altered FTO “obesity gene” require a high-protein FTO genotype and a 2-year change in body composition and fat distribution in response to weight-loss diets: the POUNDS LOST Trial. diet. Such people retain an increased appetite even after eating, and dietary protein, unlike fats and carbohydrates, provides Protein, weight management, and satiety a feeling of fullness and maintains it for a long time.
People with the CC genotype of the TCF7L2 gene are indicated for Dietary fiber intake modulates the association between variants in TCF7L2 and weight loss during a lifestyle intervention. diet high in fiber and reduced in carbohydrates TCF7L2, dietary carbohydrate, and risk of type 2 diabetes in US women. . Since this gene is associated with blood glucose levels, consuming fiber and reducing carbohydrates will not only help maintain weight, but also reduce Metabolic effects of dietary fiber consumption and prevention of diabetes. risk of type 2 diabetes.
Some people can eat fatty foods and not gain weight, others are not so lucky: all the extra grams of fat immediately end up in fat reserves. To find out how fatty foods affect you, you need to analyze the PPARG gene Interaction between a peroxisome proliferator-activated receptor gamma gene polymorphism and dietary fat intake in relation to body mass. . It encodes a gamma receptor in adipose tissue, which is responsible for the oxidation of fatty acids and the division of adipose tissue precursor cells. People with the 12Ala allele of the PPARG gene have reduced gamma receptor activity, and as a result, dietary fat has little effect on their fat cell count.
In addition, milk, butter, animal fat and other sources of saturated fatty acids are contraindicated for some people. In people with the A genotype FABP2 Ala54Thr polymorphism of the fatty acid binding protein 2 gene and saturated fat intake in relation to lipid levels and insulin resistance: the Coronary Artery Risk Development in Young Adults (CARDIA) study. Eating more than 53.2 grams of saturated fat per day increases “bad” cholesterol, and they metabolize saturated fatty acids faster, which promotes fat accumulation.
In addition, some people should not drink milk at all, and not only because of the risk of gaining weight. About 75% of the entire population of the Earth, to one degree or another, has Lactose intolerance: diagnosis, genetic, and clinical factors intolerance to lactose, a disaccharide from dairy products.
The MyGenetics DNA test will help you determine what kind of diet you need: how much protein, fat, carbohydrates and fiber your body needs to lose and maintain weight, and what foods you should completely eliminate. The test results are presented in the form of clear recommendations: what to add, what to remove, and how to create a menu for the week.
Criminologists are getting stricter
The laboratory stores DNA profiles of all employees, and work areas are sterilized with ultraviolet light. “It’s even stricter in the forensic laboratory,” explains Vladislav Zavarin. “They do DNA analysis there for everyone who crosses the threshold of the laboratory. After all, if a person’s DNA ends up in the wrong place, he will become a suspect in a crime.”
Here the solution undergoes heat treatment. Photo: AiF / Yana Khvatova
When performing PCR, special reagents are added to the sample tubes. Laboratory technicians place test tubes in a device called a genetic analyzer. It establishes the genotypes of analysis participants in less than an hour. The analysis results are transferred to the computer. The minimum rate of paternity confirmation is 97.5%. Typically in the laboratory this figure is higher than 99.9999%.
The entire analysis process lasts two days. Photo: AiF / Yana Khvatova
Once analyzed, DNA samples can be stored in laboratory refrigerators for several years. Perhaps over the years, science will step forward, and from the sample it will be possible to obtain a lot of new information about a person.
Decoding the paternity test
Only a specialized laboratory can give the correct interpretation of DNA analysis.
It is quite difficult to obtain the necessary information - it is necessary to decipher the DNA analysis through sequencing. This suggests that a sequence of microstructures (multiple letter values) needs to be established.
To study a molecule, it is isolated from a biomaterial sample, and then numerous copies are made for use in the study. Using several analysis techniques, the result is deciphered: positive or negative.
Positive result
After testing is completed, the customer receives a written conclusion with the result. It is expressed as a percentage and, when paternity is confirmed, is 99.999999%. This is the highest figure.
A DNA test cannot be 100%, since 0.01% is allocated to the fact that each person has an alleged twin with a similar chromosome set.
Nevertheless, in court such a result is considered positive, and paternity is recognized as full. The test is determined differently, after which the blood relationship between the man and the child is refuted.
Negative result
A negative result is indicated as 100% and is never questioned. Therefore, if such a result is available, the customer is recommended to perceive it as the only correct one.
However, first it is worth understanding whether a genetic test always gives a true answer. If a man refuses to take a DNA test, material from his relatives - parents, children, brothers and sisters - can be used for analysis.
The result of a test on a buccal epithelium sample taken from a grandparent or grandchildren is similar to a paternity test.
“We are ten years behind the West”
The laboratory’s activities do not end with establishing relationships. Geneticists are helping investigators find missing children. For example, a child disappeared in a family, and a handkerchief was found somewhere on the road. Laboratory specialists will do a DNA analysis in a few hours. If it is established that the scarf belongs to the missing child, then the investigation is on the right track. The first 48 hours after a child goes missing are called “golden hours.” Within two days the possibility of finding the child alive is very high. In a police crime lab, this analysis can take several weeks. Then there will be practically no chance of finding the child alive. This delay occurs due to a lack of employees, their insufficient qualifications and outdated equipment. Most Russian equipment allows DNA analysis only from blood taken from a person.
The solution becomes pinkish in color. Photo: AiF / Yana Khvatova
Recently, a woman whose relative had been in an accident contacted the laboratory. He was burned alive, and his body has been in the morgue for seven months. The woman is in despair: she cannot bury the body until the examination is completed. It is unclear when this will happen: there is a huge queue for the examination. In the Tver laboratory, the examination can be carried out in just two days.
The laboratory assistant introduces the DNA preparation into the solution. Photo: AiF / Yana Khvatova
“Russian genetics is still far behind the West, by at least 10-15 years,” says Daria Popova. - That's a lot. Graduates of our universities often do not study the latest advances in the field of genetics.” Genetics is best developed in England. There, a DNA analysis is performed on all people who have at least once been prosecuted for any violation and entered into the database. If in the future a person commits a crime, his identity will be immediately established. In Russia, DNA is taken only from the most bloodthirsty criminals - rapists and murderers, who will not leave prison until the end of time. Also in England, DNA is taken from children and old people suffering from memory problems. The sample is stored in the laboratory. If a person is lost, specialists will take a DNA sample from him and compare it with the laboratory one. In the West, behavioral genetics is actively developing, which makes it possible to trace how a person’s habits and character, and his taste preferences are inherited. DNA studies are even carried out on flies. In our country no one is doing this.
The laboratory has the most modern equipment. Photo: AiF / Yana Khvatova
What to do to build muscle
Staying in shape requires exercise and a proper diet, but how much and how much you have to exercise to achieve results depends on your genetics.
For example, Variability in muscle size and strength gain after unilateral resistance training. , in some people, after 12 weeks of progressive exercise, muscles can increase by 59%, while in others - by only 2%. Imagine: three months of hard training in the gym and 2% that you won’t even notice!
Your ability to build muscle depends on many factors, such as:
- Quantity Potent myofiber hypertrophy during resistance training in humans is associated with satellite cell-mediated myonuclear addition: a cluster analysis. stem cells in myofibrils. These cells are in a state of rest until the muscles need to be restored after exercise. They then fuse with muscle cells and donate their nuclei for repair and growth.
- Expression Cluster analysis tests the importance of myogenic gene expression during myofiber hypertrophy in humans. myogenin, a gene responsible for the growth of muscle mass, as well as the IGF-IEa gene, responsible for the synthesis of mechanical growth factor (MGF). In response to muscle damage, MGF awakens dormant myoblasts—young muscle cells—and accelerates muscle growth.
- The body's response to muscle damage. The VNTR IL-1RN gene variant affects Variable number of tandem repeat polymorphisms of the interleukin-1 receptor antagonist gene IL-1RN: a novel association with the athlete status on cytokines, enhances the inflammatory process and accelerates recovery after training.
Even if you are one of the people who cannot gain muscle, do not despair. Just accept that you need to train harder and longer than others.
It is not yet possible to repair genes
The laboratory in Tver is equipped with the most modern equipment. However, even this is not omnipotent. There are different types of genetic analysis - for kinship, for determining the risk of dangerous diseases in a person, for his ethnicity, for the presence of pathologies in a child in the early stages after conception. Some tests require different equipment. However, science does not stand still: genetic analyzers have already appeared that do everything that science can do today.
After the laboratory technicians calculate the exact percentage of relationship, the specialist can draw up a conclusion and send it to the customer. Photo: AiF / Yana Khvatova
The laboratory will soon begin conducting research on medical and perinatal genetics (embryo research). Already now, using DNA, you can find out the genetic passport of a person’s health: what pathology threatens him and how to avoid it. Specialists can identify a person's risk for inherited cancer. And by taking the blood of a pregnant woman, you can see all the abnormalities of the child - from Down syndrome to other genetic disorders. Unfortunately, modern science cannot yet eliminate these diseases. “Currently, developments are underway to eliminate and treat genetic defects,” says the head of the laboratory. “It’s too early to talk about great successes in this area, but we are on the threshold of another genetic revolution.”
DNA chain of 16 fragments. Photo: AiF / Ksenia Zheleznova
Another Russian DNA research center operates in Samara - they specialize in medical genetics. To the doctors of the hospital. M.I. Kalinina is contacted to predict the development of diseases and check compatibility with their chosen one.
Medical and Genetic Center of the Hospital named after. M.I. Kalinina. Photo: AiF / Ksenia Zheleznova
Why are genetic tests needed?
Imagine that you have an encrypted letter in your hands. You will be able to read it as soon as you receive the code from the cipher. In a similar way, information about the human body is encoded in the genome. A genetic test is its decoding and analysis of the information received.
To read the genomic code, you need to extract a DNA molecule from blood or saliva. This molecule consists of gene sequences, like a Christmas tree garland of colorful balls.
Doctors compare the sequences with those in the scientific database. For example, scientists know that three specific genes increase the risk of developing diabetes. If they are found in the person being examined, then it can be assumed that his likelihood of getting sick is higher than in people who do not have a similar combination of genes.
Some time ago, I also wanted to undergo genetic testing after seeing an attractive advertisement for a medical center, but after talking with doctors and figuring out what was what, I abandoned this idea. And that's why.
Genetic compatibility of spouses
“No more than two couples a month come to our clinic - not as many as we would like. Unfortunately, not all doctors know that this analysis is very informative, so they do not use it in the examination,” says a biologist at the medical genetic consultation hospital. M.I. Kalinina Marina Dubinskaya . The doctor invites you to the genetic laboratory where such tests are carried out.
In the office there are several automatic machines that extract DNA. The biologist places the blood samples into a thermal cycler.
Three DNA tests of a man and a woman appear on the computer screen. Based on the drawings, the geneticist determines the compatibility of married couples according to the Acheulian system. Such data helps determine the possibility of infertility.
“We make three informative loci that show whether partners are compatible or incompatible. Even if the indicator is negative, there is no need to worry, the doctor explains. “First of all, we send such patients for diagnostics, after which the necessary treatment is selected for them.”
Device for PCR diagnostics (polymerase chain reaction). Photo: AiF / Ksenia Zheleznova
Marina cannot remember any examples of absolute incompatibility. Complete genetic incompatibility is extremely rare. There is partial incompatibility, which can be adjusted during pregnancy planning, during the period of conception and directly during pregnancy.
Biologist Marina Dubinskaya with the DNA chain of patients. Photo: AiF / Ksenia Zheleznova
As a rule, all married couples are compatible, but they may have problems conceiving and carrying a pregnancy to term in the early stages. The mother's body can produce antibodies that are immune to the baby's antibodies. In such cases, women are treated with special cells before pregnancy.
“A good geneticist will not only analyze the results of the analysis, but will also offer a number of procedures that will allow you to get pregnant and also safely carry a child,” says biologist Marina. “We have a patient who took care of her child’s future in advance and did a DNA test to determine compatibility with her partner. She underwent treatment and is now 20 weeks pregnant.”
Modern DNA amplifier. Photo: AiF / Ksenia Zheleznova
Can you blame genetics for your addictions?
The lucky ones who tried smoking and didn't become addicted most likely did so because of their genes.
Genetics determines The genetics of smoking and nicotine addiction. the number of receptors with which nicotine will interact and how quickly it will be processed. These factors increase the risk of addiction and influence Association between genetic variants on chromosome 15q25 locus and objective measures of tobacco exposure. on how many cigarettes a person will smoke per day.
It's the same with alcohol: many people drink it, but only a few develop a strong addiction. The tendency to alcoholism is determined by Genetics and alcoholism by 45–65%, and the remaining percentage by the environment.
“Knowing your DNA comes in handy.”
The medical genetics clinic is crowded. One of the patients is a resident of the Ulyanovsk region, Ekaterina Polyakova. DNA research is not carried out in their city, so she specially came to the Samara laboratory.
“My relatives have a hereditary disease - diabetes. I want to check my predisposition to this disease. It’s scary, of course, but this is important knowledge for me; if the result is positive, I can start preventing diabetes now,” says patient Ekaterina.
Photo: AiF / Ksenia Zheleznova
Biologist Marina sends the girl to the analysis room. The patient is offered to donate blood from a vein, or make a scraping from the inner surface of the cheek. Ekaterina donates blood. Next, doctors extract the DNA. Then the amplification reaction is performed and the result is detected.
“DNA can even be isolated from hair and bone tissue. But this requires labor-intensive methods that take entire days. And using the express method through blood, it’s quite easy, quick and inexpensive,” says doctor Marina. — DNA tests have become much cheaper. A single analysis costs around 300-500 rubles.”
Photo: AiF / Ksenia Zheleznova
To take blood tests, there is a queue at the medical genetic consultation. Marina explains this by the fact that people’s interest in their genotype is increasing. The biologist is sure that knowledge of her gene set will be useful in everyday life.
“For example, for women taking oral contraceptives. About 1-2% of women are carriers of the Leiden mutation, says the doctor. — If a woman who takes hormonal contraceptives has such a mutation, the percentage of complications increases 15 times. A doctor who knows about a woman’s genotype will think a hundred times before prescribing these drugs to a patient.”
Methods for decoding DNA
DNA decoding is a rather complex and time-consuming procedure. To decipher a molecule, it must be copied many times, then divided into parts and deciphered each of them in turn. For convenience, the lettered bases that make up the genetic code are painted with special dyes so that after being illuminated by a laser it is easy to recognize and read.
Another modern research method is very similar to tomography. In this process, a DNA molecule is passed through a special microscopic device. During the passage, the vibrations produced per minute of time are read, which are immediately output to the computer. Based on changes in such oscillations, it is possible to decipher the necessary code.
What is DNA testing?
DNA is a deoxyribonucleic acid that is found in the human body and contains unique information that is transmitted at the genetic level from generation to generation. A strand of DNA contains 46 chromosomes. This is the main carrier of the human data of each individual person laid down at conception, which is unique and similar only to your blood relatives. That is, genetic information via DNA is transmitted only from parents to children. Thanks to such features, it is possible to establish the percentage of gene coincidence between relatives or completely eliminate this assumption.
Considering the uniqueness of deoxyribonucleic acid, scientists, through genetic testing based on molecular tests, have achieved the highest results in determining blood ties. For DNA examination, biological material from two or more people is needed (if necessary). There are no problems with collecting material, since genetic information is contained in our blood, saliva and other natural secretions. The only difficulty today in conducting DNA testing is its high cost and the availability of specialized laboratories not in all cities of Russia.
Why is saliva testing required?
The standard sample for DNA profiling is blood. For examination, 20 ml of venous blood is sufficient. This material is considered the highest quality and most reliable. However, there are many situations in which it is not possible to take a blood sample.
For example, when establishing a close relationship, biomaterial is needed from the alleged father, mother and child. And if a man or woman refuses to donate blood for analysis, the person concerned resorts to non-standard samples.
These include nails, hair - always with the root, since the hair itself is a dead cell, sperm, personal and hygiene items. And, of course, saliva.
How is a gene different from a genome?
The entire hereditary material of an organism, which contains 3.1 billion nucleotide pairs, is called the genome.
The process of constructing new proteins from suitable 20 amino acids is carried out by the movement of the ribosome along RNA. But the four nucleotides present in DNA are not enough for such coding. Nature has found a way out - it uses not the nucleotides themselves, but their sequences of three elements - the genetic code. This approach allows you to program as many as 64 amino acids. And although nature does not need so much, scientists have already thought about the potential of amino acids.
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DNA under a microscope
DNA cannot be seen under a regular microscope: they are suitable for studying cells, viruses, blood composition, etc. And electron microscopes of our time do not have enough sensitivity to show the details of the structure of deoxyribonucleic acid strands. Also, modern digital microscopes illuminate the sample with a stream of electrons, and this stream is too strong, it can damage the chains of the heredity molecule or even break them. But this limitation will be overcome in the near future, which will make it possible to study in more detail the structure of the heredity molecule and its interaction with RNA.
How are genes different from DNA?
Genes and DNA are usually identified, but they are different concepts. Genes are a formalized part of a chain, with a beginning and an end. Proteins and RNA (ribonucleic acid), a single-stranded “mirror” of DNA, are encoded there. Each gene contains a characteristic sequence of nucleotides. Genes encoding the structure and behavior of proteins occupy only 2% of all DNA. Another 1% of genes encode RNA. About 80% of all genes provide auxiliary functions, including compact packaging of DNA. But scientists have not yet understood what a fifth of DNA is responsible for.
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Analysis price and time
How long it takes to get the information obtained from the analysis depends on what test you use, where it is performed and what it is analyzed for. From the date the sample was taken, results may take anywhere from a few weeks to a few months. Prenatal testing results are usually available more quickly because time is an important factor in pregnancy decisions. The doctor or genetic counselor who orders a particular test will inform you about the costs and time frames associated with that test.
Approximate waiting times for results:
- Paternity test: tests take three days to a week to process. This is relatively quick, but these tests can also take longer, sometimes up to several weeks, depending on how quickly the lab processes the results.
- Doctor-Ordered DNA Tests: Depending on the type of DNA test your doctor orders, results take anywhere from three days to two weeks.
- DNA Ancestry Tests: Tests provide results within six to twelve weeks.
The price of a genetic blood test is quite high due to the rarity of the examination and a number of other factors. The cost starts from 6,000 thousand rubles. up to more than 100 thousand rubles. depending on the nature and complexity of the test. If more than one test is needed or multiple family members must be tested to get a meaningful result, the price also increases.
