Genetics. The first law of Mendel

A monk of Czech descent, Gregor Mendel, conducted experiments in 1856-1866, which later became widely known. As a result of his research, a new science was born - genetics. The fundamental law for its development was Mendel 's First Law. As a prototype, pea vegetable was selected. This was due to the presence of a variety of varieties, which have clear distinctions between them on certain grounds. In addition, these plants are easily grown and crossed. As a result of careful planning of experiments, careful implementation of them, as well as the implementation of a large number of laboratory experiments, reliable statistical data were obtained. As a result, Mendel's First Law was first discovered, and then the subsequent ones.

Essence of experiments

So, in more detail about how the First Law of Mendel was discovered. At the beginning of the study, plants were selected that had distinct differences for any pair of characters: for example, in the arrangement of flowers, apical or axillary. Cultivating each type for several generations, Mendel noted the suitability of them for use for experimental purposes. Experiments consisted of crossing by transferring the pollen of one plant to another. Reliable results of experiments were obtained due to careful observance of a number of precautions. In particular, stamens from flowers that were pollinated, subsequently removed, special caps on flowers were worn to prevent transfer of pollen from other plants.

Results of experiments

From the seeds harvested from hybrids, in all cases, plants with axillary flowers were obtained. This sign became dominant. The presence of the apical flowers was accepted as a recessive trait. After the experiment, the plants of the first generation were left for self-pollination. The resulting hybrids had a part of the axillary and part of the apical flowers. According to Mendel's assumption, the second type was also present in the first generation. However, the severity of this feature was inadequate. That is, it manifested itself in a latent form. In carrying out such experiments with some pair of characteristics, about three-quarters of the hybrids had characteristics that were manifested in the first generation. The fourth part of the offspring in the second family of bred plants had properties not found in the 1st. The more experiments were put, the more the result approached the ratio 3: 1. As a result of these studies, Mendel's First Law was derived.

conclusions

When studying the characteristics of crossed plants - the parental samples were presented with two similar signs - hybrids were given one of the hereditary factors. In this case, the properties of the first generation in the offspring did not merge, but retained the individuality. As a result of the research, reliable information was collected in order for Mendel's First Law to be derived. His formulation is as follows: "The signs of a certain organism are determined by a pair of internal factors (genes). In the second generation, derived from mono-hybrid crosses, about a quarter of the offspring have recessive traits. " It should be noted that Mendel's First and Second Law were not first perceived by the scientific community. Subsequently, in the works of other scientists, these provisions were proved again. As a result of new research, the chromosome theory of heredity was formed .