History of genetics

Hippocrates has developed a theory resembling that later proposed by Darwin, who called it ‘pangenesis’. 

According to this view, each part of the body produces something which is then somehow collected in the ‘semen’, the germ cells.

Anaxagoras, the Athenian philosopher (500-428 BC) had similar views: …’in the same semen are contained hairs, nails, veins, arteries, tendons and their bones, albeit invisible as their particles are so small’. 

A comprehensive theory of inheritance was developed by Aristotle. He also believed in a qualitatively different contribution by the male and the female principles to procreation.

More or less casual observations on natural or accidental hybrids in plants were made over a long period, beginning with the observations of Cotton Mather on maize in 1716.

In 1857, Gregor Johann Mendel began his famous study of the pea plants in his garden; by 1866 he would publish the results of his cross-breeding experiments, the first step in understanding heredity and how it passed from one generation to another. He founded the concept of the gene, which has proved so fertile ever since.

Eventually, scientist discovered a substance that every living organism carries within its cells – DNA. The discovery of DNA’s double-helical structure changed the way genetics was done, with a profound shift to molecular interpretations of the gen and its function.

James D. Watson, Francis Crick and Maurice Wilkins held that the structure settled the question that DNA is the genetic material. The structure immediately suggested to them how genes can replicate themselves.

In 1944, Oswald Theodore Avery, Colin MacLeod, and Maclyn McCrathy discovered that DNA was the special hereditary material that almost all living organisms need to reproduce and survive.
History of genetics

Gregor Johann Mendel

Gregor Johann Mendel Gregor
Johann Mendel was born in Heinzendorf, a village near the border between northern Moravia and Silesia, in Austrian Empire on July 22, 1822. He was an Augustinian priest and scientist, and is often called the father of genetics for his study of the inheritance of traits in pea plants. In 1851 he was sent to the University of Vienna to study, returning to his abbey in 1853 as a teacher, principally of physics.

Mendel began his experiments with the hybrid cultivation of pea plants in 1856. After spending eight years carrying out experimental work in the monastery garden, he reported on the results of his observations at the meetings of the Association for Natural Research in Brno on the evenings of February 8th and March 8th, 1865. His experiments brought forth two generalizations which later became known as Mendel's Laws of Inheritance.

Mendel's attraction to research was based on his love of nature. He was not only interested in plants, but also in meteorology and theories of evolution. Mendel often wondered how plants obtained atypical characteristics. On one of his frequent walks around the monastery, he found an atypical variety of an ornamental plant. He took it and planted it next to the typical variety. He grew their progeny side by side to see if there would be any approximation of the traits passed on to the next generation. He found that the plants' respective offspring retained the essential traits of the parents, and therefore were not influenced by the environment. This simple test gave birth to the idea of heredity.
Gregor Johann Mendel