Tom Shakespeare

On the discovery of the nature of inheritance

When an obscure Augustinian monk read his paper on Experiments in Plant Hybridization at the Brno Natural History Society in 1865, nobody noticed.  The paper only received three citations over the following 35 years.

But that monk, Gregor Mendel, had made a crucial breakthrough, the result of breeding tens of thousands of pea plants in the monastery gardens.  Far away in England, Charles Darwin was causing controversy with his Origin of Species, but it was Mendel who first discovered how characteristics were passed down through the generations, and who coined  the terms recessive and dominant inheritance.  Before Mendel, it was thought that parents’ characteristics were blended in their offspring.  From observing his peas, and doing the maths, Mendel realised that it was a question of two distinct options, a 25% or 50% or 75% chance, depending on the trait.

It was a turning point in the history of genetics.  Mendel had discovered what Thomas Hardy called “the eternal thing in man”,

Projecting trait and trace
Through time to times anon,
And leaping from place to place
Over oblivion.

To me, this scientific break through has personal relevance, because my own family has been marked by those simple mechanisms of Mendelian inheritance.  My father was born in 1927 with the condition achondroplasia, a form of dwarfism caused by a rare dominant genetic mutation.  My mother is average height, which means they had a one in two chance of a disabled baby – that’s me – or an average height baby – which was my brother.  My own two children are both short.  Our family photos illustrate biology text books, a perfect example of Mendel’s laws.

Mendel eventually gave up experimental science and became abbot of his monastry.  It wasn’t until the 1930’s, decades after his death, that the new wave of experimental genetics put together the ideas of Charles Darwin and Gregor Mendel to form what became known as the modern synthesis.  And the rest, as they say, is biology.

Footnotes, resources and further reading

Article in celebration of the BBC's Year of Science (2010), Moments of Genius - a moment in the history of science chosen by Tom Shakespeare: Mendel’s discovery of the laws of inheritance.