Gregor Mendel, a monk and teacher from Central Europe, chose common garden peas, or Pisum sativum, for his experiments in genetics because peas are easily grown in numbers large enough to be useful for his experiments and their reproduction can be altered. Pollen could be transferred from one pea flower to another with a paintbrush.
Mendel set out to investigate the patterns of inherited traits from parent to offspring during a period of eight years in the mid-1800s, publishing his work in 1866. His work involved selective cross-breeding of the pea plants across several generations with a view to observing inherited traits.
At the time, it was believed that the traits of both parents blended in their offspring. What Mendel found during his research, however, contradicted that theory. He found that certain traits appear in only two versions, with no intermediate or blended version. The pea flowers, for example, were either white or purple, and the seeds either yellow or green.
Mendel's work results in important discoveries that make up the foundation of genetics as it it understood in modern science.
- He discovered the fact that traits are inherited unchanged by reason of what he called "units," which are, in fact, the genes themselves.
- For each trait, offspring inherit one gene from each parent.
- A gene may not be expressed in one generation but carried and passed along to the next.