Mendel’s basis of modern genetics – if only Darwin had known

The fourth in a series of articles that investigates contributions to Charles Darwin’s evolutionary theory (read the first article here, the second article here and the third article here), this piece highlights the work of a man who lived at the same time as Darwin, and who made a significant contribution to his evolutionary theory, albeit in hindsight.

Although Darwin had no concept of genetics or DNA, he understood that traits were passed from parents to offspring (the mechanism was still a mystery). Had he only come across the writings of Gregor Mendel (1822-1884), he would have had greater insight into what we call genetic inheritance.

Indeed, not many scientists of the 19th century were exposed to Mendel’s work. While his original paper on the Mendelian basis of genetics was published in 1866, it took the scientific community a long time to take note of it. Sadly, the significance of Mendel’s work was only realised years after his death.

Mendel, a devout Catholic and friar, spent a great deal of his time cultivating pea plants in a monastery. He was interested in the traits that were passed from parent plant to offspring and the patterns in which this happened. He found that certain traits were passed down with a higher ratio than others (to be precise, there was a ratio of 3:1 for these traits).

Though he couldn’t have known it at the time, his work helped develop the theory of dominant and recessive genes, a central component of modern evolutionary thinking. Certain genes tend to dominate the “lottery” that is genetic inheritance. Dark hair and freckles are two examples of genes that are more likely to be passed on, rather than blonde hair and pale skin.

Unfortunately, the gravity of Mendel’s lifelong work with peas – he cultivated nearly 30 000 plants – was only realised much later, mainly because the concept of genetic inheritance had yet to enter popular discourse. A shift in paradigm was required from the view that species are static, to the view that species are constantly evolving.

It was only in the 1900s that Mendel’s name began to be mentioned in papers and research, and today it is virtually synonymous with the intricate theory of genetic inheritance.