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 a meet in the middle height of three-and-a-half-foot plants.
If you cross purple flowers with white flowers, you get either purple or white flowers. At least with pea plants, you do not get in-between lavender flowers.
On top of those findings, Mendel discovered 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 such as height and flower color were passed from generation to generation in pea plants 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.
Sources And Further Reading:
- Gregor Mendel: 1882-1894
- Mendel, Gregor. "Experiments in Plant Hybridization" (1865); trans. and reprinted in Classic Papers in Genetics, ed. J. A Peters (1959) and in Genetics: Readings from Scientific American, intro. by C. Davern (1981).