DNA - the history of the study

The presence of nucleic acids, i.e. DNA and RNA, is a common feature of all known terrestrial organisms. All life is based on the coexistence of these nucleic acids with proteins, but it is not entirely clear how the relationship between DNA and proteins developed. According to some hypotheses, proteins existed first, and then nucleic acids were formed, but now most proponents seem to adhere to the idea that the original substance was a nucleic acid capable of biological evolution. However, according to the world theory of RNA, RNA first played a major role, and only then took over DNA. However, the evidence in favor of such hypotheses is always indirect, since there are not enough old DNA samples available. Life originated several billion years ago, but after several tens of thousands of years, the amount of DNA decreases to one hundredth of the initial state. However, research in the journal Nature from 2000 to 2002 describes the discovery of bacterial DNA samples up to 450 million years old stored in salt crystals, and there are a number of other, more or less reliable studies.

Deoxyribonucleic acid was described in 1869, when the Swiss physician Friedrich Miescher investigated the composition of pus from hospital dressings. From the nuclei of leukocytes present in this pus, he obtained a certain amount of nucleic acids, which he collectively called nuclein. At the beginning of the 20th century, Phoebus Levene recognized that DNA consists of sugars, phosphates and bases.

For a long time, little was known about the functions of DNA. The first evidence of the role of DNA in the transmission of genetic information was obtained in 1944 as a result of the Avery-MacLeod-McCarthy experiment conducted by Oswald Avery together with Colin MacLeod and Maclean McCarthy. A series of experiments with the transformation of pneumococci has shown that DNA is the genetic material of cells. Additional evidence was provided in 1952 by the Hershey-Chase experiment.

Probably the most famous milestone in DNA research was the discovery of its three-dimensional structure. The model of the right double helix was first presented in 1953 in the journal Nature by D. D. Watson and Francis Crick, later Nobel Prize laureates. They were based on an analysis of X-ray diffraction performed a year earlier by Rosalind Franklin and Raymond Gosling and published in the same issue of the journal Nature. Another article in this issue was presented by Maurice Wilkins. In 1957, the then well-known Crick introduced a series of rules called the central dogma of molecular biology and describes the relationship between DNA, RNA and proteins. A year later, the famous Meselson-Stahl experiment allowed us to determine the method of DNA replication in cells. The genetic code was deciphered in the early 1960s by Har Gobind Khorana, Robert W. Holley and Marshall Warren Nirenberg 토토사이트 는 신규 회원을 위한 환영 보너스와 일반 플레이어를 위한 로열티 보상을 포함하여 플레이어에게 다양한 보너스와 프로모션을 제공합니다. 이러한 보너스는 전반적인 게임 경험을 크게 향상시키고 큰 승리의 기회를 높일 수 있습니다.