The color of a native European

The company "Genotek", Geektimes

Part of the world's population is born with fair skin. The homeland of mankind is Africa, the skin color of our ancestors was dark. For a long time, the hypothesis that light skin was inherited by Europeans from Neanderthals remained popular. DNA analysis of Neanderthals showed that there were indeed people with different hair and skin colors in their population. Modern research refutes the popular hypothesis, proving that the skin color of the inhabitants of Europe began to change after the extinction of the Neanderthals. Gradually, the shade approached the modern. Now the change in skin color is explained through physiological processes.

A tall man with fair skin who assimilates lactose well is a typical description of a modern Caucasian youth. In reality, these European youths are not the same as they were 8000 years ago. Why Europeans have light skin is in the new material from Genotek.

Dividing the skin of an ancient man

If you are in the company of an anthropologist, geneticist and evolutionist, and you are bored, ask: "Did the ancestors of modern humans and Neanderthals interbreed?" Disputes on this topic have been going on for several decades. According to research, Neanderthals had an attractive appearance, there were different shades of hair and skin. On the one hand, we have a lot in common with Neanderthals. DNA analysis today shows what percentage of the Neanderthal genome is in your own. Gene variants associated with the development of diseases such as diabetes and Crohn's disease were inherited from Neanderthals. However, the common features in the genome could have been inherited by both us and them from a common ancestor. And the mechanism of pigmentation change is different from that used by modern people.

Go out of my way to move

After moving to Europe, people needed to change their appearance and diet. The current hypothesis is that the spread of these traits in the population was motivated by the need for vitamin D. This vitamin can be produced in the skin under the influence of ultraviolet light, or it can come from the outside with dairy products. So, in the course of evolution, 2 solutions for the problem of vitamin deficiency were proposed at once. The first solution is to make the skin susceptible to ultraviolet light. The second solution is to create an enzyme for the effective production of vitamin from dairy products.

Veronika Musatova, consultant of the Genotek Medical and Genetic Center: "Vitamin D is necessary for normal bone formation and growth. It regulates the metabolism of calcium and phosphorus. With a balanced and full diet and periodic exposure to the sun, there is no reason to worry. In case of signs of hypovitaminosis, loss of appetite, insomnia, seizures appear, osteoporosis and osteomalacia develop – softening of bones."

83 ancient people

If earlier each new genome of an ancient person was an event, now scientists are working on a full-genome scale with data from several ancient people. Anthropologists from Harvard analyzed 83 genomes of ancient Homo sapiens people from archaeological sites in Europe dated from 8000 BC to the present. The main task of the study is to find genes that for some reason have become dominant in the European population over the past 10 thousand years. For comparison, the genomes of modern Europeans from the 1000 Genomes project were used. The beauty of working with the genome is that it is a sequence of symbols – to solve a number of tasks, it is enough to determine the genotype in a specific position. In total, 390000 genomic loci (individual positions in the genome) were analyzed. Among them, only 30,000 have a known relationship between genotype and phenotype (external feature).

The appearance of a native European

Harvard anthropologists divided the results into 3 groups depending on the nature of the changes. "Fashion trends" were constantly changing with the population; "random changes" occurred regardless of external causes, and "fundamental metamorphoses" significantly transformed the population under the influence of natural selection. The genes belonging to the latter group interested scientists the most. They are associated with skin pigmentation and nutritional characteristics. In the distant past, Europeans were dark-skinned people who did not drink milk. The work of lactase in the human body began after the domestication of cattle and after the migration of steppe tribes of Black Sea cattle breeders, that is, about 4,300 years ago. The change in diet caused a demand for the development of specific physiological signs.

Adaptation to milk

The work of the genes that changed with the arrival of man in Europe was associated with metabolism. The strongest selection pressure was observed in the locus, which is associated with the viability of lactase in Europeans. The replacement of just one nucleotide affects how this enzyme will be synthesized, and, therefore, the ability to digest milk sugar – lactose. Also, 2 genes were associated with metabolism: FADS1 and NADSYN1. The FADS1 gene is involved in fatty acid metabolism, and the NADSYN1 gene is associated with vitamin D levels.

Change skin color

In the new population of Europeans, 2 genes affecting skin pigmentation, SLC24A5 and SLC45A2, have spread. The skin is a complex multifunctional organ of the human body. At the cellular level, skin pigmentation depends on the work of melanocytes – cells that produce melanin. The SLC45A2 gene helps in the creation of melanin, and the SLC24A5 gene regulates the concentration of calcium in melanocytes. Curiously, inhibitors (substances that inhibit the work of the gene) of the latter are available as commercial injection kits that lighten the skin. Mutations in SLC24A5 and SLC45A2 independently appeared in Europe at about the same time. That is, at a time when there were two independent light–skinned populations - hunter-gatherers from Sweden and Middle Eastern farmers, the main population of Europe was different from them. Even 8,500 years ago, hunter-gatherers from Luxembourg, Spain and Hungary had dark skin.

Alexander Rakitko, author and developer of the Genealogy DNA test (Genotek), which examines the genetic origin of a person: "We analyzed our database and found out that for the Russian population, in addition to the SLC24A5 gene variant, which is responsible for light skin, there are others. At the same time, according to the database of the 1000 Genomes project, there are no other variants in the Central European population at all. In fact, this confirms that the population of Russians differs from the population of Europeans, and comparing the human genome from Russia with the genome from the world database can show significant differences."

Eye Color Logistics

Another mutation that has become entrenched is associated with the HERC2/OCA2 genes. The work of these genes is associated with the delivery of dark pigment to the iris. The HERC2 gene in this case is a phone call, and the OCA2 gene is a truck that delivers the pigment. If something is wrong on the line or with transport, then the pigment is not delivered, and the eyes remain bright. "By default" the eyes have a dark color, light shades are associated with the fact that the pigment is missing or does not reach its destination.

Adam, Eve and me

From a conceptual point of view, this study takes us to a new level of obtaining information about the past. It is possible to compare the data of ancient and modern people and find not only the specific features of populations of the past, but also the general mechanisms of evolution and adaptation in human history. The result of genotyping is information about the genotype at the locus. In the study of evolution, the main interest is focused on the change of genotypes over time.

Restore skin color by DNA

Modern DNA analysis technologies complement the image of ancient people with features that cannot be read from skeletal remains. They were able to recreate the contour of the face from the skull before, now the eyes, hair and skin have gained color. In addition, personal information is disclosed, such as metabolic features, for example, lactose intolerance, predisposition to obesity and resistance to diseases. To build such models, researchers work with the genome. Height, weight, chronic pathologies are complex signs that can be learned about a person from DNA. The dynamics of changes in the genome over time can be traced by comparing the data of ancient and modern people. By analyzing changes, evolutionists and anthropologists evaluate the contribution of natural selection and population change over a specific period of time.

Tabula rasa

These studies show that external features are a means of survival. Now a person is less dependent on the environment, and his phenotypic signs are his own history. And skin pigmentation is not a tool, not a symbol of superiority, not a special right and not special powers. Skin pigmentation is simply a phenotypic trait that has changed over the course of evolution due to adaptation to certain environmental conditions.

This material is prepared by the Genotek team. We are engaged in genetic research. One of our projects is the DNA test "Genealogy", which tells about the origin of a person, his ethnic composition and haplogroup, and also reveals the proportion of the Neanderthal genome. We are actively researching scientific publications on the topic of human origin and will share with you the results of our work. Read us.

Portal "Eternal youth" http://vechnayamolodost.ru 09.11.2016