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By Olga ZHUKOVA, Cand. Sc. (Biology), head of the Human Genetics Laboratory, N. I. Vavilov Institute of General Genetics, Russian Academy of Sciences; Sergei RYCHKOV, laboratory research worker
The N. I. Vavilov Institute of General Genetics has published the first volume in the series The Genofond and the Genogeography of the Population envisaged in many volumes. The volume now off the press deals with the gene pool of Russia's population (The Genofond of Russia's Population, ed. by Professor Yuri Rychkov and Academician Yuri Altukhov). It presents data on human genetic markers among the population of Russia and neighboring countries. This is the first ever thesaurus on the gene pool of the peoples and nationalities inhabiting our country. We learn that its diversity here approaches half of the world's level. Our correspondent Igor Goryunov has interviewed Olga Zhukova and Sergei Rychkov of the Human Genetics Laboratory of the N. I. Vavilov Institute about the work done and further plans.
- With the publication of your work on Russia's gene pool our country is no longer a blank spot on the genetic map of the world's population. This is quite an achievement, sure. But why did we have to wait as long as that? Is it because such kind of research began too late?
- O. Zhukova: Well, in the 1920s Professor Viktor Bunak, an anthropologist, and Dr. Nikolai Koltsov, Corresponding Member of the USSR Academy of Sciences, undertook a study of the Russians and Byelorussians. And earlier than that, at the end of the 19th century, Alexander Lyubinsky, who examined Kronstadt's seamen, collected the first data on the propagation of the color vision anomaly among the population in various parts of Russia.
Even though the concept of gene pool ("genofond"), coupled to the notion "genogeography", was first introduced in 1928 by Alexander Serebrovsky (subsequently elected to the USSR Academy of Sciences as corresponding member), native populations came to be studied along the population-genetic (statistical) pathway: that is in separate populations one identified the propagation pattern of gene markers essential for the passage of stable characters from generation to generation. Here in Russia scientists always sought to represent the characteristics of various ethnic groups through a number of characters, be it blood groups, polymorphous variants of proteins and enzymes, or physiological indicators. And so forth. Our laboratory, drawing upon a vast body of material obtained before, started collecting genetic data on the gene pool of the Soviet Union's population late in the 1970s, with Yuri Rychkov still in charge. His experience in studying ethnic nationalities of Siberia, Caucasia and Central Asia furnished a groundwork for our research and, in the long run, for our work on the gene pool of Russia's population. As to the delay in the publication of this volume, it was largely due to the economic difficulties which our country has been facing of late. For nearly fifteen years we were unable to publish our work prepared for publication. Scientific problem solving had little to do with that.
- Now what is a people's genofond, or gene pool? And how does it differ from the human genome that has been sequenced recently?
- S. Rychkov: Genome is the complete set of genes that is replicated within a cell of a particular individual. This is the information enabling this individual to survive in the ever changing conditions of the environment and to pass it to progeny.
Gene pool is the complete set of genes and any other replicating fragments of DNA proper to a particular population within the confines of a territory it inhabits. The genome and the gene pool differ as much as a separate individual does from a people at large. For instance, one may be blond or dark-haired, while a population may include both fair- and dark-haired individuals. In fact, the characteristics of a definite group of people is determined not by the presence of this or that character, it depends on its frequency. That is to say, a gene pool may include all possible characters, whereas differences in their occurrence allow to distinguish one gene
pool from another, compare gene pools in different population groups, study ways and forms of their interplay, and so on.
Separate individuals, the gene carriers, respond to changes in environmental conditions (natural and social ones) by an ability to procreate, i.e. produce offspring, and thus pass a definite number of copies of their genes that change the pattern of a particular gene pool. In turn, cultural and economic traditions, say, the mode of conjugal ties work to stabilize its characteristics. In the final analysis, the gene pool is not merely a sum total of all the genomes, it is the inner resource of a population accounting for the forms of its reaction to changes of man's environment (natural and social).
- What do we get from gene pool studies?
- O. Zhukova: First of all, we try to understand what laws underlie the existence of a gene pool, how it lives and changes, what processes occur in it, and their causes. Also, we are studying its response to the impact of various factors, and its characteristics essential for a population's survival should environ-
mental conditions change this way or that.
Populations interact in the course of their historical development. Migrants transfer their genes and cultural traditions from one population group to another. Populations seek to expand the bounds of territories they inhabit through cultural or military expansion. Some peoples dissolve in the course of these natural processes, while others change both culturally and genetically, and thus become different than their ancestors. Children, inheriting the genes of their father and mother, are not the carbon copies of their parents. The same is true of peoples who, inheriting the genes of their ancestors, are not at all identical to them. And yet the gene pool is a repository of historical memory.
The geography of genes changes in time, largely as a result of migrations. Before Russians crossed into Siberia in the 17th century, the local Mongoloid population had virtually been devoid of the Rh-negative factor. But taking a look at the present genogeographical map that indicates all the peoples inhabiting this territory, we shall see a considerable increase in the occurrence of the Rh-negative factor.
- Ecologists, politicians and other experts are pointing to the degradation of the gene pool of our nation. What is the real situation?
- S. Rychkov: The gene pool can change, it can evolve, but it cannot expire unless it is destroyed through the extermination of a particular population group which will be unable to pass its genes to offspring. The body of genetic information accumulated in the course of its evolution will thus be gone. Otherwise, should a particular ethnos disappear from the face of the earth, it will pass its genes to the gene pools of other peoples it has contacted, and these genes will live on in them. The genes present in the contemporary population have come down from man's distant ancestors in a succession of generations. This means that not one population and not one culture has vanished into thin air. The passage of genetic and civilizational information has never ceased.
Birth and death are the two boundaries of life. Once coming to be a population should die a natural death or else evolve into a new one which has the same destiny in the future. Yet experience gained by its ancestors does not disappear, it is passed from generation to generation, from parents to their progeny. Consequently, genetic information on a population of long ago is preserved actually for an infinitely long time. For instance, studying Neolithic bone remains in Siberia (from about 4 to 5 thousand years ago), we have found that the trace characters of the then populations are still present in the gene pool of the indigenous peoples.
- But why is nature taking such tender care of the gene pool of peoples who are on their way out? Say, as a Moscow resident I can leave for the North and stay there for quite some time, perhaps for the rest of my days, with no genes of aboriginal peoples in me.
- O. Zhukova: It depends. You don't know how you'll fare over there. If you don't have genes enabling you to adapt to local conditions, you shall leave those parts, and do it pretty fast.
- S. Rychkov: The population gene pool has a different time scale- in generations, not years. You can go to the North all right and live comfortably off. But what about your offspring? If the genetic information you will pass to your descendants does not enable them to adjust to new conditions (low temperatures, precipitation, food, different daylight hours, and so forth), they will have but slim chances of staying on. However, adaptation in the course of several generations, intermarriages with autochthons and the like could give
Occurrence of the Rh-negative factor in Siberia. 17th century.
your progeny not bad survival chances. Pulling up stakes is not enough, what counts is the offspring that will multiply. Moving to other places is your conscious choice, while the ability to survive in generations to come depends on the adaptive resource of people's gene pool.
The gene pool accumulates information in the course of its evolution. This information, retained in a variety of forms of the selfsame genes, enables a population to find an adequate response to external changes. We know that migration processes provide for genetic diversity of a gene pool, while isolation tends to solidify the characters responsible for survival under definite conditions, it eliminates "noxious" characters and, in the final count, detracts from genetic diversity. These two countervailing processes-fixation of "useful" and accumulation of redundant information-enable a population to meet the challenges of a sudden change in environmental conditions.
According to the data obtained by our laboratory, Russia's territory accounts for something like 50 percent of humankind's genetic diversity. Small wonder, for the diversity of any country's gene pool is determined by the size of its territory, by the number of ethnic groups and nationalities, and the way they interact with one another and other peoples. Our country occupies a large part of Eurasia, and it is populated by people of more than 100 nationalities. (Studying gene pools, we should consider ethnic, not administrative, boundaries.) No other country can boast of such ethnic diversity. Now take the United
States: that country has a huge number of immigrants from all over the world. But, like a melting pot, it turns all of them into Americans. In Russia, however, ethnic groups live within the bounds of their cultural traditions and territories, and thus are able to keep their population and genetic structure. At the same time, a moderate level of migration within this country adds to the diversity of their gene pools which also benefit from our numerous historical contacts with many nations of Europe and Asia.
- What is the practical significance of your work?
- O. Zhukova: Accumulation of data on the gene pool makes it possible to look back into history and reconstitute the picture of the evolution of a population structure. This is an important factor. What is more, such data allow us to come up with well-substantiated fore-
Occurrence of the Rh-negative factor in Siberia. End of the 20th century.
casts and look ahead into the future of Russia's peoples. Even today we are able, reliably enough, to assess the risk of certain diseases and locate regions of the highest hazard. Besides, we can pinpoint the causes: whether this risk is due to natural factors or is the consequence of man's economic and cultural activities. In this case we can warn against making such errors again.
Our knowledge of the genetic diversity of our country's peoples will give us a better understanding of the significance of the gene pool which, according to Alexander Serebrovsky, is the same natural resource as is petroleum or coal, for instance. Only then shall we be able to take a better care of it in a variety of ways.
- Are you through with your studies of the gene pool of Russia's peoples?
- O. Zhukova: No, not at all. The gene pool is a very complex and multidimensional object-so much so that it cannot be studied in full. Once we know all about the gene pool, we will be able to unlock the mystery of life. Well, at the beginning of our work we ran into a paradox: the native Russian population and the European part of Russia came to be studied... least of all! We sent a number of field parties which helped us in collecting genetic information in many regions of European Russia. This work took a few years. Simultaneously, we studied and evaluated a vast body of data amassed over decades of research-both available before and those hard of access. And thus we can now acquaint the scientific community with unique data on the gene pool of Russia's peoples.
Our book is but the first stage of our project on studying genetic processes on the vast expanses of the former Soviet Union. Our research findings are to be published in a five-volume edition. Nauka Publishers are having another volume, Russia's genogeographical atlas, under press. Coming next will be the volumes on ethnic genetics, ecological genetics, and genetic processes in the populations.
Interviewed by Igor GORYUNOV.
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