Despite the fact that heredity has been known for a long time, the nature of this process has remained a mystery for a very long time. The very first and simplest assumption was that the characteristics of both parents are “mixed” in children, so the children are a cross between a mother and a father. However, the ancient Romans already understood that this process should take place in a different way. In the middle of the 19th century, the experiments of the Austrian monk Gregor Mendel allowed us to approach the modern understanding of the mechanism of heredity. Using his own observations of plants as an example, he showed that traits do not mix, but are transmitted as discrete (isolated) units to the next generations. His discovery was not given much importance by the scientific community, and it was not until 1900 that botanists Hugo de Vries, Carl Erich Correns, and Erich Cermak obtained results similar to Mendeleev’s and confirmed his hypothesis. In 1909, the Danish biologist Wilhelm Ludwig Johansen called those discrete units responsible for the transmission of heredity “genes”, and in 1910, scientists were able to establish that genes are located on chromosomes. The function of chromosomes became even clearer in 1944, when it was established that hereditary information is contained in DNA. At the beginning of the 21st century, the global Human Genome project was completed, where scientists from different countries joined forces to study DNA in detail. As a result of the study, about 25,000 genes were identified and described. Knowledge of the human genome has made an invaluable contribution to the development of medicine and biotechnology. Modern genetics is an extensive tree of derived disciplines. Its specialized sections began to be considered as major independent sciences: human genetics, cytogenetics, nutrigenomics, molecular genetics, metagenomics, immunogenetics, environmental genetics, and others.

To understand what DNA deoxyribonucleic acid looks like, you can imagine a “zipper” twisted into a spiral. DNA is stored in the nucleus of every cell and contains the information that makes the body what it is. Each half of the helix consists of nucleic acids corresponding to each other, which together make up base pairs (there can be up to three billion of them in one cell). These sections of the nucleotide sequences encoding functional products are called genes. The entire set of genes obtained at birth makes up the human genotype, and all the hereditary material contained in the cell is called the genome. Proteins serve as the lever by which DNA controls the body. The human body uses them to work the immune system, digest food, heal wounds, catalyze chemical reactions, provide communication between cells, and so on — that is, for complex physiological interactions that ensure the health and life of the body. In order for protein synthesis to occur, DNA is first “rewritten” (transcribed) into RNA (ribonucleic acid), after which the information contained in it is transferred (translated) into protein. This process is called gene expression. In addition to coding DNA (the one that synthesizes proteins), there are genetic “switches” in the body that turn genes on and off. Such non-coding DNA makes up about 98% of all human DNA and is often referred to as “junk”. However, despite its name, it is also necessary for the regulation of genes and the functioning of the whole organism. We can say that genes are inherently eternal. The life of a single DNA molecule is short, but each of them is able to control its reproduction: copy itself and continue to exist for millions of years. But genes can change — this is influenced by various conditions external to the cell — and human health depends on these changes (mutations), because they are the root cause of many diseases.

Human genes are like small computer programs embedded in humans since ancient times. For example, the insulin receptor gene in adipose tissue served our ancestors well tens of thousands of years ago: it helped us store as many calories as possible in conditions of constant food shortage. However, today there is no need for a person to escape from hunger, so the gene does more harm than good: problems such as overweight and obesity are developing at double the rate. The modern computer age requires humans to update their genetic code, and scientists have already been able to change it. It is in genetics that many see an opportunity to overcome many serious diseases, including cancer. To date, there are promising techniques of gene therapy against cancer: oncolytic viral, prodrug, immunotherapy, as well as therapy using stem cells. Today, technology allows you to edit the information contained in DNA. This allows specialists to “remove” harmful genes and activate useful ones. They are developing individual programs to significantly improve human health: techniques such as genomic analysis, gene therapy, and molecular diagnostics using biomarkers are already yielding positive results. An example is the experiment of Chinese scientists. In 2018, the world’s first twins with a modified genome were born in China. With the help of gene editing, scientists have created protection against the human immunodeficiency virus in children. The children are completely healthy and are not predisposed to the development of this disease, and they are being monitored. The aim of the experiment is to strengthen the health of the twins and get closer to increasing the health of all mankind. Scientists are actively studying methods to combat aging, and they are already identifying the genes that control this process. When comparing the genome of young and old people, using a computer, it is possible to identify places where there is a greater amount of genetic damage. The researchers want to use their own cellular mechanisms to reverse the accumulation of errors in the mitochondria and thereby increase the life span of the cell. The future of genomic medicine is not far off due to the computer revolution. In just a few years, everyone will be able to get their own genomic map, which will indicate hidden diseases. Recent discoveries in the field of genetics have shown that many ideas about the mechanisms of diseases were erroneous. Due to the accelerated development of technology, scientists will soon be able to see the genetic structure more clearly, and then, as a result, therapy methods will make it possible to treat and prevent diseases with greater accuracy, based on the individual characteristics of each patient.