Rights: The University of Waikato Published 21 November 2007 Download

Using peas, maths, and a lot of patience, Gregor Mendel uncovered some of the secrets of the gene. Nobel prize winner Sir Paul Nurse explains some of the monk's ground-breaking conclusions.


Sir Paul Nurse: To talk about the gene, I have to talk about a monk - a gardening monk, called Gregor Mendel. And Gregor Mendel was a monk, in Bruno, now in the Czech Republic, and he belonged to an order, an order that was interested in science. He was a meteorologist, but later in his life he turned his attention to heredity: to trying to understand why it is that offspring resemble their parents ... what is the nature of heredity.

And he decided, as many have before him, to study plants and plant breeding to try and work out what was going on. He experimented with a number of plants, and like many good scientists decided to dismiss most of them because he couldn’t make any sense of the results. [He] chose to focus on one particular species, the pea, because he could make sense of the results.

What he did with the pea was to go through the different variants that were available - short plants, tall plants, plants for different coloured flowers, the different types of seeds, and so on - and then crossed the different varieties to each other and see what happened. And he studied these by crossing two parents, and taking the offspring, crossing them to each other, and so on.

What he concluded is that there was a particulate form of inheritance and that was giving rise to these very simple numbers. In other words, what was happening is that each parent was contributing a particle, we would now call it a gene, to the progeny produced. So if you had pollen and ovules, then each gamete that was being formed from a parent would produce one particular particle, and the offspring would have two particles that would be responsible for determining a particular characteristic.

Working through this, he came to the conclusion that particles were being handed on. These were unchanging elements of heredity which had information in them that determined characteristics in the plant. And each organism had two such particles for each such characteristic, and they only handed on one of those to their offspring.