Russian Russian gene Pool on the Russian Plain

Blood, saliva and bugsKonstantin Ioch, "Russian Reporter"
If earlier the answer to the question "Who were my ancestors?" could only be given by family traditions and archives, then recently genetics has also been taken to help a person find out his pedigree.

Specialists have learned how to decipher one of the most informative and promising sections of DNA for studying – the Y chromosome. It exists only in men and is transmitted from father to son and to grandchildren almost unchanged. The Laboratory of Population Genetics in Moscow has been studying the gene pool of Russia for a long time. The correspondent of "RR" visited the laboratory and gave blood for analysis.

Now we are going to set up a small experiment – to determine which is better to use for our purposes: cotton swabs or special brushes," Olga Vasinskaya, a graduate student, an employee of the Laboratory of Population Genetics, introduces me to the scientific wilds in the tone of a mentor.

There is a small plastic bag on the table – in such policemen from films collect evidence. The package is signed with a black marker: "Bukkashki". Genetic jargon. From the "buccal epithelium" – the layer on the inside of the cheek, which is used for DNA research. Olga puts on rubber gloves – a necessary condition when working with samples – which makes the similarity with the investigation only stronger. Population geneticists are detectives – they unravel a complex tangle of migrations and mutual influences of peoples.

Olga opens the package and extracts smaller bags from it. They contain ordinary cotton swabs, which can be bought at any pharmacy, and special brushes. The bags are also signed: "Oleg", "Khadizhat", "Sveta" – like any scientists, geneticists use what is at hand as experimental material – themselves.

I am offered to see with my own eyes how my DNA is isolated. To do this, Olga and I go up to the second floor of the Medical and Genetic Research Center of the Russian Academy of Medical Sciences - the laboratory occupies several rooms in the basement of the center. Now it is the only population laboratory in the country equipped with the latest technology necessary for the study of the gene pool of peoples.

With a large test tube containing my blood, we return to the "operating room" – that's what I mentally called the room where DNA is isolated. With the help of a dispenser, Olga measures 100 microliters of blood and transfers it to a tiny test tube, which stands in one row with the others. A large test tube with the remaining blood in it is assigned an individual number and placed in a special refrigerator. There are four such refrigerators in the "operating room". There are eleven in total in the laboratory. They look and size more like safes – huge iron boxes. The temperature inside is minus 70 degrees. With such freezing, blood and DNA samples can be stored forever. These refrigerators-safes contain priceless material – the result of many years of work by geneticists to collect samples. They were mined in expeditions throughout Russia, Ukraine, Belarus, Kazakhstan, Kyrgyzstan, Tajikistan and even Afghanistan… There is no such DNA collection anywhere else in Russia.

– First of all, we need to prepare a DNA sample, which we will analyze, – Olga continues in the tone of a mentor – she stands the role. I specifically asked her to comment on every step, as if I were a new graduate student who needs to be taught to isolate DNA. – For this, only the top layer on which the cells are located is cut off from a cotton swab.

With a confident movement Olga makes an incision, then removes the thin top layer with tweezers and places it in a test tube.

In general, DNA can be isolated from blood, saliva and buccal epithelium in various ways. The epithelium is the most accessible for research. DNA is extracted from it relatively quickly and simply – by purification using various sorbents. The amount of DNA extracted is always individual and depends, among other things, on how carefully the sampling of the material will be carried out. The more cells can be scraped off the cheek, the greater the DNA yield.

When all the samples are placed in test tubes, Olga fills them with a lysing buffer – a cell-destroying solution. The die with test tubes is placed in the thermostat. The samples should be kept in it at a temperature of 69 degrees for about an hour, then the contents of the cells will be released into the solution.

If Marx is mixed with Agatha ChristieWhile the cells are being destroyed, in order to replenish my meager knowledge in genetics, I go to the office of the artistic director, – this is how Elena Vladimirovna Balanovskaya, Doctor of biological Sciences, head of the laboratory, is called by the staff.

– How will genetics help a person who wants to learn about his ancestors?

– To answer this question, you need to know what genetics can do in principle and what it cannot, – Elena Vladimirovna begins from afar. – Parents give us their genetic text. What is it? From your father you received, for example, the collected works of Karl Marx, and from your mother – the collected works of Agatha Christie. At the time of the transfer, the volumes were randomly mixed: one volume from dad, the second- the third – from mom. The fourth, fifth, sixth – Marx, then Agatha Christie again. When you pass the genetic text to your child, you will again randomly pass Karl Marx mixed with Agatha Christie from this set. But your wife also received a library: from her father, for example, Tolstoy, and from her mother – a cookbook. The child will receive a mixture of four libraries already: then Tolstoy, then Agatha Christie, then Marx, then a cookbook.

But there are two small exceptions, insignificant parts of the genome are homogeneous genes. If the father – in this small part of the genome – has given you the collected works of Karl Marx, then you will give it to your son, he to his, and so this "teacher's" library will pass in complete safety through the paternal line to grandchildren and great-grandchildren. This is the Y chromosome. At the Department of Genetics, they even wrote a poem about her: "Even though she is small and ugly, all the male power is with her."

The second exception is mitochondrial DNA. It is not located in the nucleus, like chromosomes, but in the cell itself, in energy stations – mitochondria. Therefore, it is transmitted only through the female line together with the egg – from Eve to all her daughters. Men also have mitochondrial DNA obtained from their mother, but they cannot transmit it. It turns out that a person has two lines that geneticists can trace – from Adam and from Eve.

– If the genetic text is transmitted unchanged from Adam and Eve, then how do scientists know any history?

– As the scientists themselves say, genetics is the science of typos. There are, for example, chronicles – one of them, the other. Which one was earlier, which one later? The copyist worked and made mistakes. The following scribes will repeat these mistakes and make new ones. The dating is formed by errors. We will not specify the date with absolute accuracy, but we will be able to determine which one is earlier and which one is later. Geneticists work the same way. In the process of rewriting genetic texts, typos sometimes occur. These typos fix the branches of the tree, which are called haplogroups – both for the Y chromosome and for mitochondrial DNA. We know that our very distant ancestors possessed such-and-such stem haplogroups, and we designate them with letters: A, B, C, D, M, N ... This is a large tree with its roots going back to the time of the emergence of modern man, that is, to a depth of about a hundred thousand years.

For clarity, Elena Vladimirovna takes out a large poster with a tree of haplogroups:

– It is compiled according to the latest data. A, B, C, J, I – rough division into the main haplogroups. Analyzing the entire chromosome is expensive and long – it's the work of an entire institute for a couple of months. Therefore, population geneticists study individual sections of DNA – loci. Mutations occur in loci. Here is one sequence of nucleotides – AGTCAATAT… When rewriting the genetic text, a typo occurred – the replacement of the first nucleotide with another – A by T, that is, a mutation.

– What gives a person knowledge of his haplogroup?

– Knowing which branches are earlier and which are later, which are stem and which are smaller, we can trace the migration paths and restore the history of peoples. But it is possible to move on to a single person only after at least the main peoples of the world have been studied. Otherwise, we would be able to tell a person only about his own genetic text, but nothing about his history and geography. That's why we go on expeditions all over Eurasia, studying where haplogroups are found.

Russian Russian Gene Pool on the Russian Plain and an article published in the prestigious scientific journal The American Journal of Human Genetics were the results of the laboratory's research. These works showed the huge genetic diversity of the Russian people on the Y-chromosome. The southern and central Russian populations formed a single cluster with Ukrainians, Poles and Belarusians – eastern and Western Slavs have much more in common in Y-chromosome markers than other European peoples. Russian Russian populations, even on the scale of Europe, form their own cluster, far removed from the main core of Russian populations – a powerful Finno-Ugric layer can be traced here.

Another interesting result: the genetic trace of the Tatar-Mongol yoke has not been found. That is, the expression "Scratch a Russian – you will find a Tatar" does not correspond to reality. The Russian gene pool is a typical European one.

A third of namesakes are relatives– Or another task.

Now our laboratory is working on the project "Namesakes or relatives?" – continues Balanovskaya. – His goal is to find out how surnames originated and spread in Russia, how often simple, seemingly namesakes turn out to be relatives. Thanks to this project, people can learn about the origin of their family. We issue a certificate to each participant, which lists the substitutions found in his genome, and indicates which of the namesakes is a closer relative, and who is a distant relative. We also give a table and a map. The map is similar to the physical one. You can use it to trace where your genetic relatives live, and thus determine where your roots may be from.

– And what is the connection between surnames and haplogroups?

– Since both the surnames and the Y chromosome are transmitted through the male line, there is a historical connection between them. If surnames were inherited as steadily as the Y chromosome, then the historical connection would be unambiguous: which surname, which haplotype. Unfortunately, this connection is disrupted both by frequent "mutations" of the surname – changes in spelling, the appearance of a different surname in the descendants than the father's – and by cases of illegitimate children, adoptions, and the transfer of the surname from the mother. But the most important reason for the disruption of communication is polyphilicity, the repeated occurrence of the same surname in different people. For example, the surname Ivanov appeared in a variety of places in genetically different people.

– What are the first results of this project?

– The collection of namesakes was carried out by us with the help of "volunteers" on the Internet and included namesakes living not only in Russia, but also far beyond its borders. Such a randomly assembled group should not have included namesakes from the same population, where most of them could turn out to be relatives who had time to forget about their kinship.

Of course, 308 people representing 38 surnames are not enough to conduct a full-fledged statistical analysis. But it is already possible to identify some trends.

Firstly, the degree of polyphilicity of the surname does not depend on the number of namesakes studied. This indicates the reliability of the results. Secondly, about a third of all namesakes can be considered as relatives. Thirdly, both rare and frequent surnames can be polyphyletic. Minimal polyphilicity, as expected, is characteristic of rare surnames.

– How is the relationship between namesakes established?

– We analyze haplogroups and haplotypes. Haplogroups are the hour hand of evolution. They are determined by mutations in the so-called SNP markers. Such mutations occur very rarely. But there are also STR markers - haplotypes. This is the minute hand of evolution. Completely different mutations occur here: one repetition of a "motif" of several "letters" of the genetic text is added or disappears. For example, a parent has a simple motif of four letters "SATT" repeated 12 times, and his descendant has 13. Such substitutions occur frequently.

To analyze namesakes, we use a panel of 17 markers used in forensic examination: the coincidence of all markers allows us to identify a person or resolve issues of disputed paternity. And in our case – to assume that two namesakes are relatives. If two namesakes on 16 markers are completely the same, and one is different, then they are most likely also relatives, but not so close. Etc.

My Polish ancestorsBy the time I returned to the "operating room", the destruction of the cells had already ended.

After thoroughly mixing the cells with a buffer on the device, which is called a "stirrer" in the jargon of geneticists, but in reality – microspin, Olga takes out clean test tubes and moves the solution with the DNA in it into them with the help of a dispenser. The next step: adds "Nucleos" to the test tubes – a sorbent on which DNA is glued. Olga puts test tubes with a solution and a sorbent on a die.

– Now you need to turn the die like this, – Olga makes a rotational movement with her brush, – for ten minutes. I suggest you do this fascinating thing, and he marks the time.

I work meekly as a "stirrer".

After 10 minutes, Olga adds a new solution to the test tubes. Again, a series of mixing and precipitation follows. Then the solution is removed from the test tube, and what is left, Olga dries in the thermostat – until the entire salt buffer evaporates. This is the last stage of purification – now there is only DNA and sorbent inside the test tube.

Olga adds "Extragen E" to the test tubes – a substance that separates DNA from the sorbent. As a result, the DNA ends up in a liquid – it remains only to collect this solution.

– The extracted DNA needs to be analyzed. We do this on special devices. There is a Real Time PCR – "real–time PCR" - Olga points to a bulky device that looks like a printer. – The device is connected to a computer. We calculate SNP markers on it. And STR markers and mitochondrial DNA are calculated on another sequencer, it is in another room.

Olga takes out a small plastic die with cells. The die is drawn along the edges – vertically and horizontally. Each cell has its own address – like the cells on a chessboard. The dispenser instills DNA into cells. Loads a special program that will track the process, enters data: in which cell which DNA sample is located. Then he instills a special reaction mixture into the cells.

– With the help of this mixture, a PCR polymerase chain reaction takes place, – says Olga. – Its meaning is that a small piece of DNA that we are examining is copied exponentially: if there was one piece, then after PCR there will be millions of them.

Olga opens a small shelf on the side of the device, inserts a die into it. Sets the reaction parameters: determination of the haplogroup of my Y chromosome and the total amount of isolated DNA for the participants of the experiment. Starts the process. Real Time PCR starts buzzing.

– And what happens inside is unknown?

– I know. A laser is installed inside, which scans the die and remembers it in the state in which it is at the very beginning. Then PCR is started. After the reaction is completed, the laser scans the die a second time and analyzes the changes – the program outputs the result based on the difference between the initial and final signals.

How the reaction goes, you can watch on the monitor – and for each sample separately.

The reading takes about an hour. Finally the result is ready.

– The DNA output from simple cotton swabs and from special brushes turned out to be about the same, – sums up Olga. – As for your haplogroup, it is N1c1. The second most common among Russians is 19% of the Y-chromosome fund. This is a "northern" haplogroup – it is common both in Siberia and in the north of Europe. In Eastern Europe, it is associated with the ancient pre-Slavic population who spoke Finno-Ugric languages. It is also common among the Baltic peoples of Eastern Europe: a sharp decline begins on the border with Belarus. In Belarus and Poland, it is quite rare.

To determine where my particular twig "grows" from, my DNA was also analyzed using 17 STR markers. Armed with the results, I go on a search on the Internet. Website yhrd.org – world database of haplotypes.

I set 12 markers in the search engine first. Similar haplotypes exist in Russia, Belarus, Poland, Finland, Estonia, Lithuania, Norway, Sweden, Germany, and the Czech Republic. All these are very distant relatives, the differences with them are more than one thousand years. I increase the number of markers to 17 – most of the related haplotypes with differences in 1-3 steps, which gives a difference of about 200-600 years, are located in Poland. It turns out that an ancestor who had a haplotype similar to mine already lived on the territory of modern Poland about 600 years ago. Thus, genetic analysis confirmed what I knew about the history of the genus and the origin of the surname: once upon a time, my male ancestors lived on the shores of the Gulf of Riga or the Gulf of Finland, and in the Middle Ages moved to Poland.

Portal "Eternal youth" http://vechnayamolodost.ru31.08.2009