At the end of the 20th century, in the process of studying the composition of the genetic code , a new scientific branch arose. It began to be called molecular paleontology. It was found that traces of the evolution of the species can be detected in the human genotype. Scientists have learned to extract data from petrified remains belonging to creatures that lived in ancient times. The information received has significantly changed ideas about the early stages of human development. The findings laid the foundation for new research. Their results disproved previously existing ideas about the picture of the evolution of the world on the planet.
Research by A. Wilson
A professor at the University of California at Berkeley claimed that the ancestors of the human race descended from one woman. She once lived in Africa. Her descendants subsequently settled in other continents. As a result of their extensive distribution, a genetic diversity of people arose. The team, led by Wilson, developed two fundamental concepts within which research was conducted.
Main ideas
According to the results of a comparative analysis of proteins, it was found that in the course of molecular evolution, neutral mutations accumulate at a constant rate. This was Wilson's first idea. The rate at which changes in genes occur due to neutral point mutations is constant over time. In this regard, it can be used as a kind of evolutionary chronometer, with which you can date the departure of a particular branch from the main trunk. This was the second idea. As a result, it all boils down to a fairly simple arithmetic problem, where with known speed indicators and parameters of the path of movement, it is necessary to determine the time.
Comparative studies
They were started in 1987. For research by Wilson, mitochondrial DNA was taken, not nuclear. The latter is a small ring molecule. It consists of 16 thousand pairs of nucleotides. They form 37 genes. Of this amount, the ability to mutate is detected in no more than 2%. This is due to the fact that most genes are vital. Nuclear deoxyribonucleic acid includes 3.2 billion pairs of nucleotides.
Meanwhile, the determining factor was not only the size that mitochondrial DNA has. Wilson was also guided by other criteria. In particular, it was found that the X chromosome is inherited only along the female line. In the process of fusion of the sperm and egg during fertilization, the destruction of the sperm organoid in the cytoplasm occurs. As a result, the X chromosome is only transmitted from the mother to the fetus. This circumstance makes it possible to trace the predecessors of the individual along the female line.
Simply put, each person receives mitochondria from his mother, she - from his own and so on. Accordingly, you can build a line with which you can look into the most distant past. In mitochondrial DNA, neutral mutations accumulate at a constant rate. In addition, it does not recombine. From this it follows that differences in the nucleotide composition are caused only by mutations.
Family tree
Having established that all inhabitants of the planet have such a chronometer, Wilson began an analysis of human genealogy. For the study, samples were taken of 182 different types of mtDNA from 241 individuals. This number includes representatives from each race of 42 nationalities. Of course, young nations are more homogeneous in the genetic sense, while the older ones are characterized by a larger spectrum of mutations that were accumulated during their existence. The likelihood that the DNA pattern matches in unrelated individuals is 10-15, the identification accuracy is 10-7. Each inhabitant of the planet differs from the other by 1 nucleotide out of a thousand.
Wilson's group investigated the D-loop. This is a special hypervariable DNA region, the length of which is 300 pairs of nucleotides. It is a neutral zone. In this region, the mutations that occur do not lead to pathologies and do not give any advantages over the owners of other sequences. As a result, Wilson built a family tree. It indicated the greatest difference in mitochondrial genes in Africa. All studied samples were reduced to the original single nucleotide sequence.
Thus, Wilson explained the descent of people from one woman. However, he did not argue that she was at that far time the only one on the planet. According to the results of mathematical modeling, it was found that the effective population size was not less than 10 thousand.
Research by other scientists
Having established that mitochondrial Eve is the only mother of all individuals living on the planet, Wilson went further. Having a known mutation rate, he was able to establish its age. Wilson determined that mitochondrial Eve lived approximately 200-150 thousand liters. back. This woman turned out to be older than the Neanderthal man.
Information on the analysis of deoxyribonucleic acid was obtained by other scientists. So, for example, Satoshi Khorai pointed out that modern individuals appeared about 200 thousand years ago in Africa. From there, they moved to Eurasia and rather quickly replaced Homo erectus from there. Moreover, the mixing of mitochondrial genotypes almost did not occur. After some time, Satoshi Khorai tried to calibrate the “chronometer”. According to updated data, the age of today's man is 143 thousand years.
Other research groups have also found that the first individual appeared in Africa. At the same time, scientists analyzed nuclear genes. Resettlement, according to researchers, occurred no earlier than 100 thousand liters. back. British scientists studied a fragment of a nuclear gene that is responsible for the synthesis of B-globin. This site was analyzed in 349 residents from different regions of the world. According to the results of the study, it was also found that the origin of people is connected with the territory of Africa. Similar conclusions were made by many other scientists.
Thus, the discovery of Wilson gave impetus to other studies in various laboratories on the planet. All the work that has been done by independent scientists indicates that the place where the mitochondrial Eve appeared was East Africa.
Comparison with a linguistic tree
An attempt to analyze molecular genetics and language distribution processes was made by Qually-Sforz. The comparison showed that the tree, built according to the results of genetic research, corresponds to the linguistic one. Thus, a combination of genogeography and ethnic geography was revealed.
Mitochondrial Eve and Y-chromosome Adam
During Wilson's life, an attempt was made to trace the paternal line of all individuals inhabiting the planet today. According to preliminary analysis, it was confirmed that both mitochondrial Eve and genetic Adam appeared in Africa. The study established a number of interesting facts.
The Y chromosome has a size of 60 million nucleotide pairs. It does not recombine, and therefore differences in composition are due to mutagenesis. More accurate studies were conducted by Professor Underhall. He collected material for analysis from almost all regions of the planet. Y-chromosome is only in men. Accordingly, she passes exclusively from father to son.
According to the results of the analysis, it was found that the first man appeared at about the same time as the mitochondrial Eve - about 150-160 thousand years ago. The difference in age fits into the error of the calculation method. Similar conclusions were drawn by another independent research group led by M. Hammer.
Mitochondrial Eve: Refutation of Established Theories
From the above, we can draw the following conclusions. In Africa, about 150-180 thousand years ago, the first people arose . About 100 thousand years ago, they began to migrate along the ecumenical. Moreover, they replaced all hominids living in the territories without crossing with them. About 40 thousand years ago, the first people appeared in Europe. Further studies yielded very surprising results. So, Professor Svante Paabo was able to extract mitochondrial DNA from a fragment of a vertebra that belonged to a Neanderthal man, which was first discovered in 1856 and lived about 50 thousand years ago. According to the results of a comparative analysis, it was found that this hominid is not only an ancestor, but even a close relative of modern individuals.
Different directions of evolution
The revealed differences were so significant that scientists came to the conclusion that the evolutionary branches of the species could and, in fact, had to go in different directions 600 thousand years ago. The existing variety of Homo sapiens mitochondrial DNAs is 24 substitutions, and 32 for Neanderthals. This fact indicates that the latter go beyond the scope of species variation in humans. Accordingly, Neanderthals form a separate direction of evolution and belong to a parallel and at the same time dead-end branch.
Confirmation of conclusions
The results of studies conducted by Paabo radically change the idea of anthropogenesis. In this regard, it became necessary to verify the findings by a group of independent scientists. A fragment of the Neanderthal bone was examined by M. Stoneing, a follower of Wilson. After analyzing the remains of a child who lived about 30 thousand years ago, the scientist received the same data as Paabo. Accordingly, the conclusions of the latter were fully confirmed. After some time, a group of German researchers analyzed Neanderthal mitochondrial DNA. The result also confirmed the previously put forward hypothesis. According to paleontologist K. Stringer, humanity is on the verge of forming a unified theory, which will unite archaeological, genetic, paleoanthropological and linguistic evidence of the African model.
Spiritual aspect
The synthesis of all the above directions can bring humanity closer to unraveling the mysteries of its origin. Meanwhile, according to a number of authors, anthropogenesis cannot be reduced to a purely scientific issue. In their opinion, the arrival of people in the world is not only a material, but also a spiritual phenomenon. The authors cite scripture excerpts in support of their position. Since there are some material remains of creatures that are close to a person by morphological characteristics, the question arises of determining the place in the process of evolution in which the individual becomes, in fact, a person.
Conclusion
Scripture says nothing about the mechanism of creation. Moreover, it reports on the fact of the creation of man by God. The main in this process was the inspiration of the body, as a result of which the person ceased to be an animal. As St. Filaret of Moscow, the creation was not a one-time action, but a continuous and gradual formation. It is this sacred moment - when God blew the Holy Spirit into the body - that is the beginning of true human existence, according to adherents of religious theory. Discussed on this subject and St. Gregory of Nyssa. In his work, he wrote that man was built last after vegetation and animals. Nature, in a consistent way, went to perfection. However, Scripture itself does not explain this process. At this point, spiritual theory comes to a standstill. It is assumed that scientists must follow the path of "ascent to perfection."