Discovering Genetics

In 1871 and 1872, Charles Darwin published, The descent of man and The Variation of Plants and Animals under Domestication, respectively. In both books Darwin talks about inherited characteristics. For example, he uses the word "pangenesis" (origin of the whole) to describe the mechanism for heredity and the word "gemmules" to describe heritable traits. The theory of pangenesis said that gemmules have heritable material from every part of the organism and the material is incorporated into the sperm and eggs. Below, we can read how Charles Darwin defined genes nine years after he published The Origin of Species. Today, those heritable traits are called genes. This is an example of how genetics and biology evolved from the ideas of Charles Darwin.

“It is universally admitted that the cells or units of the body increase by self-division, or proliferation, retaining the same nature, and that they ultimately become converted into the various tissues and substances of the body. But besides this means of increase I assume that the units throw off minute granules which are dispersed throughout the whole system; that these, when supplied with proper nutriment, multiply by self-division, and are ultimately developed into units like those from which they were originally derived. These granules may be called gemmules. They are collected from all parts of the system to constitute the sexual elements, and their development in the next generation forms the new being; but they are likewise capable of transmission in a dormant state to future generations and may then be developed (The Variation of Plants and Animals under Domestication).”

In 1860s, Mendel was a priest that was studying inheritable traits in pea plants. He knew about Charles Darwin’s theory, he agreed with some of his ideas, but no one knows why he never tried to contact him. Mendel came out with two laws.The Law of Segregation says that when an organism produces sex cells (eggs or sperm), genes separate and each cell receives only one copy of each gene. The Law of Independent Assortment says that genes assort independently during the formation of eggs or sperm. Those two laws became known as Mendel’s Laws. However, the importance if his work was not discovered until the 1900s.

In 1889, Hugo de Vries derived the word “pangen” from “pangenesis” to describe the units of the heritable material. In 1905, the biologist William Bateson shortened the term “pangen” to “gene.” Elemente der exakten Erblichkeitslehre was the first textbook that had the word “gene” and became one of the first textbooks of genetics. The field of genetics began in the early twenty century, when recently scientists realized the importance of Mendel’s work. Since that time, geneticists stared doing research to learn and discover more about genes and the mechanism of heredity.

To conclude, Charles Darwin is known as “the Newton of biology,” (Wallace) and Mendel is known as “the father of modern genetics.” Their work provided a strong foundation to the field of genetics and geneticists. In the next post, we will see how scientists started to use technology to discover more information about genetics.

Picture sources: Charles Darwin and Gregor Mendel