Pioneers of discovery of mutagen operating of irradiation

Andry Smirnov, Cheuliabinsk (kaktus.ru@list.ru)
translation from Russian by editor

The mutations are genetic changes, they are quite stable and arise owing to modify structure of a gene and serve an alone source of genetic variety inside a specie. They arise suddenly, without any transitions. To mutations it is accepted to attribute of a miscellaneous genetic conversions, bound with a core and cytoplasm of a sell. A reason of mutations can be chemical changes of a gene, small-sized and large modifications of chromosome, change of number of chromosome, and also change in genome of plastide in cytoplasm. The same mutations can arise repeatedly. On the development they can be useful both harmful, dominant and recessive (exhibited at once or only in following breeds).

Mutations meet extremely seldom in vivo. It has resulted many scientists in a conclusion about necessity of mining of paths synthetic induction of mutations. One of such paths is the effect by irradiation. This problem was studied by the American scientific Hermann Joseph Meller (December 21, 1890 - April 5, 1967).

For mining of this problem he was awarded with the Nobel Prize on physiology and medicine for discovery of appearance of mutations under influencing of x-ray irradiation. With appearance of nuclear weapon your discovery, according to which one a heredity and changes of aircraft attitude can deliberately change in laboratory conditions, gained new and terrible value. Meller convinced of necessity of a nuclear test ban.

In 1927 Meller has reported on an International genetic congress on his work on Drosophila. With the help of X-rays it managed to receive for flys a great many mutations. The frequency of them, as contrasted to by natural mutation process, was increased in hundreds and thousand times. Meller found out of flys with more dark or more light colouring of a body, with diverse colouring of an eye, other arrangement of setas on a surface of a body, with twisted wings and in general without wings. The message of Meller has appeared sensational. It has put began to development of activities on synthetic calling of mutations for many species of plants and animal, and also bacterias and viruses. The mutations are caused by the diversified radiation sources: by rays of a Roentgen, alpha, beta - and gamma - radiation, ultraviolet rayss and neutrons of sufficient intensity. This intensity has appeared much superior natural earth irradiation.

And nevertheless the pioneers of discovery of mutagen operating of irradiation - Russian scientifics G.Nadson and G.Filippov. In 1925 they have published in publications of Russian State Roentgenology and Radiological Institute the article about obtaining mutations for yeast under operating of radioactive matters, which one concern to ionizing radiations. G.Nadson and G.Filippov selected colonies of yeast distinguished by value, form and colouring. The cells had changed properties. Irradiation strikes genes. The majority of genes in one chromosome are shown only once and control synthesizing a definite enzyme. A defeat of genes - main reason of functional changes. Certainly, it is difficult to get by irradiation in any definite gene - "target" is very small. But in a sell set of miscellaneous genes, and it is enough to get in any of them to call heritable changes of a sells.

The scientists have applied usage of irradiation to increase of efficiency of plant selection. In Russia since 1928 A.Sapegin in Odessa town and L.Delone in Kharkov town begin to apply successfully X-rays to improvement of sorts of wheat. They have created hundreds different radiomutants. A lot of forms have received A.Lutkov for barley and peas, M.Ternovsky for tobacco. The radiomutant sorts are created almost for all cultural plants. Irradiation finds operational use and in work with animal. In 1936 Soviet genetic A.Serebrovsky has put the proposal to struggle with parasitic insects with the help of ionizing radiations. The irradiation adult imago results in gross infringements of a heritable material in sex cells. Their participation in a fertilization results in loss of descendants. This idea was used by the American scientists. In the south of USA reproduced huge quantity of flys transferring from one animal to another exciters a ulcers. The chemical poisoning matters could not erase insects. To the aid came of genetics. Their operatings were, on the maiden view, a little bit strange. Instead of destruction of flys them intensively multiplied. Then have irradiated selected males. The sex cells were teleorgаnic, but germs perished at early stages of development because of mutations. Sterile males have scattered from an airplane on the large area. Their quantity exceeded quantity normal male in the nature. After pairing females sidetracked eggs, but from them nothing could develop, and the flys were not multiplied.