Mendel's 200th Birthday

Observations made by Gregor Mendel about pea plants paved the way for understanding inheritance
18 July 2022

Interview with 

Berris Charnley, ARC Centre of Excellence for Plant Success in Nature and Agriculture, University of Queensland


But first, this month marks a special day for the field of genetics: it’s the 200th birthday of Gregor Mendel. Being out in the garden gave Chris Smith pause for thought…

Chris - Now this year, I've upped my home-grown game. And one of the things I'm watering in the hot weather on my pea plants. And it's amazing to think that someone doing something similar growing and tending their peas over 150 years ago, laid the foundations of modern day genetics. The monk, Gregor Mendel, who was born this coming week two centuries ago in what is now the Czech Republic, came from a poor family but he received a very good education. It endowed him with a grasp of maths and statistics that enabled him to spot, track and understand how different characteristics of his pea plants were inherited long before anyone had any idea that DNA even existed. I caught up with science historian Berris Charnley, who told me more about this intriguing man's life...

Berris - Gregor Mendel was an interesting character, and he really has become a larger than life character. He was a monk who was living in Eastern Europe in the mid 19th century. He was in fact schooled in what was, at the time, the most cutting-edge pedagogical educational technique on the continent. And so he had a background in thinking about the world around him and experimenting as a means to find out more about the world around him. So one way of thinking about his work is as an exploration into the idea of whether God made everything all at once, or whether plants and animals do change over time in ways which we can analyse and experimentally recognise. And this was part of what he was aiming to look at in his work with peas.

Chris - What was the concept of genetics before he came along? Because where I grew up, opposite, my house was the home of John Ray, the naturalist who actually went to Cambridge; from being son of a blacksmith, became a scientist at Cambridge university. But I was surprised to read that John Ray was one of the first people to say, well, plants inherit something, meaning baby plants come from a parent plant that looks like they do. And prior to that, people weren't really in tune with the idea that things inherited something that made them look the way they did. So what did people really think about genetics and genes up until that point?

Berris - One school of thought is that when people talked about something being inherited, they were talking by metaphor to legal forms of inheritance. So they weren't discerning between what we might call cultural and biological inheritance in the same ways that we might. One of the key things that changes when people begin to reappraise Mendel's work and think about it more deeply, there's precisely a change in what this word "inheritance" means and ideas about what it is that's being passed from an adult to an offspring, and the biological basis of those ideas.

Chris - Is there evidence that he was familiar with what Darwin had been saying, because Darwin comes along a bit before Mendel - he'd written "On the Origin of Species". Darwin had seen the product of this happening, but didn't know how it was happening. Was Mendel familiar with that and then thought, well, this is some meat on the bones? Or were they completely independent of each other?

Berris - It appears that Mendel was aware of Darwin's work, but the other way around isn't true -  Darwin wasn't aware of Mendel's work. The legend is that he has a copy of Mendel's famous paper experiments in plant hybrids and it's in his library. But one can tell that he didn't read it because he hadn't cut the pages. When journals were circulated in the 19th century, they were often bound all the way around; the spine and the outers of the pages were bound and one would have to cut open the pages so you can read them. People have looked at Darwin's library and found that he didn't actually get to read Mendel's work. Darwin had his own theory of inheritance which was quite different to the work which Mendel was doing. Darwin's theory suggested there were things called "pangenes", which circulated within an animal and then passed through to its offspring. What happens in the 20th century, people bring together Darwin and Mendel's work to form what we think of as the basis for our modern ideas about evolution and inheritance.

Chris - Did Mendel have much insight into the difference that his ideas were going to make? Or was he pretty self-effacing and humble about this and thought, "well, I found something interesting here. I've written it up. I've been good to my scientific training and background. Now I'll move on and do other administrative duties." I think one commentator once put it that, that he succumbed to that disease that all academics do, which is that they get consumed by admin. They don't get to do any science anymore. What is the end of the story?

Berris - It's very true that Mendel doesn't really pursue a scientific career in the way that we might think of a scientific career. So he doesn't build on his initial discoveries and follow them through to other discoveries. He does continue doing some experiments with some other plants, but the general feeling is that Mendel feels like he's discovered something of moderate significance to what might be a special case, which doesn't really provide the groundbreaking world-shaking answers to either the question about where new types of sheep might come from, or the question about where new species of animals might come from.


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