The so-called “father of genetics”, Gregor Mendel, is famous for his experiments with peas published in 1865 and 1866. Thanks to them, this Austrian monk and naturalist laid the foundations of genetics, becoming a basic figure in the history of the science. What did these experiments consist of?
While the phenotype are those characters that we can distinguish with the naked eye, such as hair color, the shape of the eyes, etc., the genotype is what causes it, which genetically predisposes the human body to be one way or another. . Basically, the phenotype is the expression of the genotype in a certain environment. Thus, Mendel decided to study specific characteristics of a pea species, Pisum sativum , to learn more about the genetics of the pea plant.
In reality, the choice of this particular species was based mainly on two characteristics that even today are decisive when carrying out an experiment: time and money. Pisum sativum is a plant that has a very short generation time and a high descent rate, which allowed many experiments to be carried out in a very short time . In addition, the cost was very low as it was a common plant and had several varieties within the same species, such as the colors of the seeds, the pod, the type of stem, and so on.
Once the model plant was chosen, Mendel prevented it from self-fertilizing by removing the anthers (the terminal part of the flower stamens) and thus controlling the crosses it would make. In addition, to control possible uncontrolled pollen hybrids, he bagged the flowers. These measures would provide you with the assurance of obtaining reliable results for the scientific community.
Pea crosses
Once you have determined the way that will offer you greater certainty in the results, the model organism and the characters to study (the shape and color of the seeds, the color of the flower, the location and size of the stem, and the color and the shape of the pod), Mendel began to make the famous pea crosses. He first crossed two different pure varieties in one or more characters to later self-breed this first generation of offspring. And so on. He also carried out reciprocal crossings and backcrosses to reach the conclusions that would make him famous: the Uniformity Law, the Segregation Law and the Independent Segregation Law .
