In 1860, Johann Gregor Mendel (1822-1884) proposed the existence of “hereditary factors”. Like many people of his time, he had observed that children possess some of the attributes of their parents. No cellular or molecular structures were known that could explain this phenomenon. However, he was determined to investigate the rules for the appearance of parental features within their offspring. Amongst other organisms, he chose the garden pea to experiment with. After years of research, he became aware that parental characteristics were to be observed at certain ratios within the offspring.
Early in the 20th century, the experimental embryologist Thomas Hunt Morgan (1866 – 1945) provided the next milestone in the discovery of the molecular basis of inheritance. Although he initially was skeptical about Mendel’s ideas, his experiments with fruit flies offered convincing evidence that chromosomes are the structures that act as “vessels for inheritance” - for those "hereditary factors" proposed by Mendel.
In 1953, James Watson (born 1928) and Francis Crick (1916 – 2004) proposed a model to the scientific world that showed DNA as a double-helix that would soon become a symbol for modern biology. Over the next decades, more and more research was conducted, and knowledge was gained about the structure and the characteristics of the DNA.
It soon became clear that DNA is in fact what Morgan’s chromosomes and Mendel’s hereditary factors are made of. DNA is the substance that “encodes the secrets of life”.
Today, every student learns about the major discoveries that were achieved in molecular genetics over the past 100 years. However, there’s still lots to be discovered, and there are still many questions that await answers. And that is just one of the reasons why genetics is a fascinating area of biology.