What do you get when you cross a 1-foot pea plant with white flowers and a 6-foot pea plant with purple flowers?
There have always been superstitions and off-color jokes about questions like that. But Gregor Mendel, one of the most important figures in the history of biology, wanted to find out what really happens--by crossing real pea plants.
Mendel lived over a hundred years ago in a monastery in what is now the Czech Republic. He experimented with plant breeding in the monastery garden. Mendel had a hunch that heredity proceeded according to rules; he wanted to find the simplest form of those rules.
Here's some of what Gregor Mendel's experiments revealed:
If you cross a 1-foot pea plant with the 6-foot pea plant, you get plants that are either 1 foot tall or 6 feet tall--not in-between, three-and-a-half-foot plants.
If you cross purple flowers with white flowers, you get either purple or white flowers--not in-between, lavender flowers. At least not with pea plants.
On top of that, Mendel discovered that if you know the ancestry of the parent plants, you can predict, using a mathematical formula, what percentage of plants in the next generation will have purple flowers as opposed to white.
Actually, heredity is rarely so simple. But Mendel kept his plant-breeding experiments as simple as possible so he'd get clear results. His results showed that some easy-to-see traits like height and flower color were passed from generation to generation in a strict pattern.
Gregor Mendel was a pioneer in what's now called genetics. His garden experiments of over a hundred years ago revealed heredity operating with almost computer-like precision to help make the luxuriant variety of living plants.
