Mendel and his first law

The Austrian monk and scientist Gregor Mendel and his discoveries made through experiments with peas, held in the monastery where he lived, were extremely important to today knew that some of the genes and mechanisms of heredity. Their experiences were also very significant for understanding some of the gaps theory of evolution, proposed times before.

The success of his experiments consists of a set of factors. One was the very choice of subject matter: the pea Psim sativum: easy plant to grow and short life cycle, with flowers and hermaphrodites that reproduce by self-fertilization, and their contrasting characteristics, without intermediaries: yellow or green, smooth or rough, high or low, purple or white flowers, among others.

Furthermore, the monk selected and did a careful analysis, separately for each pair of the seven characteristics that identified; considered an appreciable number of individuals of various generations, and to start your first crosses, took care to choose pure specimens, observing them for six generations resulting from selfing to confirm that really only give rise to individuals like him and each other.

Performing the cross-fertilization of the male part of a plant seed yellow with a green female (parental generation, or P), observed that the children, he called the F1 generation, were only yellow seeds. Autofecundando these copies, the F2 is presented in the ratio of 3 to 1 green, yellow seeds (3:1).

With these data, Mendel considered the green seeds and yellow as recessive, dominant. Doing the same analysis for the other characteristics of the plant concluded that in all cases was the same 3:1 ratio.

With this experiment, deduced that:

• The characteristics determined by hereditary factors are inherited from fathers and mothers in the same proportion;
• These factors separate in gamete formation;
• Individuals pure lines have all their gametes equal, while hybrids produce two distinct types, also in the same proportion.

Thus, Mendel's First Law can be stated this way:

Each character is determined by a pair of alleles genetic factors called. These, in the formation of gametes, are separated and thus both parents transmit only one to his descendant.

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