Gregor Johann Mendel The founder of genetics Basics of Heredity Gregor Johann Mendel The founder of genetics

Who was Gregor Mendel? Gregor Johann MENDEL was an Austrian monk and biologist whose work on heredity became the basis of the modern theory of genetics.

When and where Mendel was born on July 22, 1822 in Heizendorf, Austria.

How he lived Johann Mendel was born into a poor farming family. At that time it was difficult for poor families to obtain a good education and the young Mendel saw the only way to escape a life of poverty was to enter the monastery at Brunn in Moravis. Here he was given the name Gregor.

F1 Generation The f1 generation is the hybrid offspring produced in the cross pollination of “P” generation plants. When two f1 members are crossed f2 generation will appear.

F1 generation

F2 Generation The progeny of self-pollinated F1 Generation plants. In the F2 Generation Mendel was surprised to find that both pure lines traits appeared. The trait that had been lost in the F1 Generation had reappeared in the F2 generation.

F2 generation

Pure Lines Pure lines are a population that breeds true for a particular trait. (This was an important innovation because any non-pure (segregating) generation would and did confuse the results of genetic experiments.) Mendel had two innovations to the science of genetics: 1. Developed Pure lines. 2. counted his results and kept statistical notes.

Mendel’s 1st law The law of segregation states that in the process of the formation of the gametes the pairs separate. When the hybrids are crossed, the four possible combinations of the genes in Aa and Aa are AA, aA, Aa, and aa.

Mendel’s 2nd law The law of independent assortment (Mendel's second law) states that characteristics are inherited independently of each other; e.g., the dominant trait of yellow seed color in pea plants can appear in combination with either the dominant trait of plant tallness or the recessive trait of dwarfness. This law has been modified by the discovery of linkage in genetics.

Law of Dominance The law states that when a (pure) dominant and a (pure) recessive trait are present. The dominant trait in the Law of Dominance will show in the hybrid organisms. The recessive trait does not disappear. It shows up again in the F2 generation.

Incomplete Dominance Incomplete Dominance is when neither trait in a contrasting pair is dominant over the other. Incomplete Dominance Is not common is most experiments. When this situation occurs, two opposite traits are combined and a blending of traits appears to happen.