Before we get into diagrams of genes and chromosomes,
let’s step back to the time before powerful microscopes—before scientists could
actually view the genetic material within a nucleus.The
pioneer in the study of genetics was Gregor Mendel (1822-1884), an Austrian monk. Mendel
studied the cross-breeding of common peas in the monastery’s garden, and in 1866
published the results of his now-famous experiments. Mendel’s creative and innovative
interpretation of his data is considered to be one of the greatest intellectual
achievements by an individual in the history of science! Mendelian genetics ultimately
revolutionized the science of biology and provided support for Darwin’s theories of
natural selection.
Mendel worked on his theories of inheritance long before
there was any evidence of the existence of chromosomes and genes. For ten years he studied
certain traits of the common pea plant, Pisum sativum. As you read through the
summary of one of his experiments, try to put yourself in Mendel’s place. You may
find yourself marveling, as I did, at his patience and discipline—and at the
creativity of the conclusions he was able to draw from his data.
Mendel studied seven traits in pea plants, each of which
had two different, distinct expressions:
