Mendel, Gregor Johann

Gregor Johann Mendel, born on July 20, 1822 in Hynčice in the former Austrian Empire (now the Czech Republic), died on January 6, 1884. The Augustinian monk Gregor Mendel is considered the father of modern genetics. He was a teacher, scientist, mathematician and a man of faith. Mendel prevailed despite adverse circumstances and, with the help of mathematics, made perhaps one of the most important discoveries in science. However, his work was not recognized until thirty years after its publication, when the term "gene" was not as common as it is today. Mendel used a simple system to develop the famous experiment that would explain how traits develop in all living things: the study of pea plants.

Although Mendel's early research was aimed at studying mice, he later used bees and eventually turned his attention to plants. Around 1854, Mendel began his research on the inheritance of traits in plant hybrids. Between 1856 and 1863, he used around 28,000 plants for these studies. At that time, it was generally believed that the heritable traits of a species simply came from the dilute mixture of traits from both parents and that future generations of a hybrid would return to its original form, which meant that a hybrid could never produce new forms.

Due to the many varieties and the fact that it was easy and quick to breed, Mendel decided to use the pea plant for his experiments. He crossed two pea plants: one variety that produced yellow seeds with another that produced green seeds; these plants form the so-called "parent generation". The result of this cross was yellow peas. He then repeated the experiment by crossing other pea plants that differed in other traits, and the result was the same: one of the two traits was produced in the parent generation. The trait that appeared he called the "dominant trait", the one that did not appear he called the "recessive trait".

Mendel pollinated the plants of the "parent generation" himself and obtained the so-called "first filial generation", consisting of plants that produced yellow seeds and plants that produced green seeds in a ratio of 3:1 (3 yellow and 1 green). He repeated the experiment with other differentiated traits and always obtained the same ratio. He then crossed plants with two or more different traits, mixing green, smooth peas with yellow, wrinkled peas. After crossing, he found that the dominant traits (yellow and smooth) appeared in the "first filial generation" and not the recessive ones (green and wrinkled).

Mendel obtained the "second filial generation" by self-pollination of the "first filial generation" and obtained seeds of all styles, plants that produced yellow and smooth, yellow and wrinkled, green and smooth and green and wrinkled seeds; in a ratio of 9:3:3:1 (9 yellow and smooth, 3 yellow and wrinkled, 3 green and smooth and one green and wrinkled).

Mendel's laws

After analyzing the results of his experiments, Mendel established his famous laws of inheritance:

• First law: the principle of dominance, which states that individuals resulting from the crossing of two purebred individuals differing in only one trait will have the trait of the dominant gene.
• Second law: the principle of segregation. It states that there are individuals who can pass on a trait even if it does not manifest itself in them.
• Third law: it is the principle of independent combination. In his study, Mendel considered not only the color but also the roughness of the seeds, but found that both traits are independent of each other in inheritance.

In 1865, Gregor Mendel gave two lectures on his studies and discoveries to the Natural Science Society in Brno in what is now the Czech Republic, which published the results of his studies the following year in its journal under the title Experiments in Plant Hybridization. However, Mendel did little to publicize his discoveries, and the few references to him from this period suggest that much of his work was not properly understood by his contemporaries. The general opinion was that Mendel had not proved anything that was not already known: hybrids eventually return to their original state. The importance of variability and its evolutionary implications were completely overlooked and, moreover, his findings were not considered to be generally applicable. Mendel himself was convinced that his discoveries were only applicable to certain species or certain types of traits. Eventually, of course, his system proved to be generally applicable and became one of the fundamental principles of biology.

In 1868, Mendel was elected abbot of the school where he had taught for fourteen years, although the loss of his eyesight prevented him from continuing his research. Due to his opposition to a law that taxed monasteries excessively, he traveled little and isolated himself even more from the rest of his contemporaries. Mendel died of acute kidney inflammation on January 6, 1884 at the age of sixty-one. His work was virtually unknown at the time, and it was not until decades later that Mendel's work contributed to the work of many leading geneticists, botanists and biologists researching heredity. In 1900, the Dutch botanist Hugo de Vries, the German botanist and geneticist Carl Correns and the Austrian agronomist Erich von Tschermak reproduced Mendel's experiments and results. However, their work was often marginalized by Darwinists, who believed that these findings were irrelevant to the theory of evolution. Mendel himself seemed to agree: "I have seen all the work, and the more I look at it, the more I am convinced that Mendelism has nothing to do with evolution".