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By studying peas, Mendel was able
to effectively limit the number of
variables, or aspects that changed discover a pattern among these factors in successive would always hide the other, “recessive” factor.
from one phase to the next, and better generations. But the short, wrinkled, and white factors did not
predict the outcomes.
Mendel began his experiments with a parent disappear from the peas’ DNA. If a recessive factor
generation, which he called P. He bred it and appeared in two parent plants, their offspring
called the next generation F1. All the F1 plants might display it. Many years later, British biologist
displayed the same factors. They were tall. Their Reginald Punnett made a diagram to show the
flowers were all purple. The peas themselves were relationship between dominant and recessive
all smooth. Things got interesting with the next characteristics. It reveals why about one-fourth
generation, called F2. About a quarter of the plants of members of succeeding generations display
were short, even though their parents were both recessive characteristics.
tall. The same proportions held true for smooth Mendel worked with his pea plants for nearly
and wrinkled peas, white and purple flowers, and 10 years. He published his findings in a relatively
the other four factors. Mendel called factors such obscure science journal in 1866. His work received
as tall, smooth, and purple “dominant.” They little attention—perhaps thanks, in part, to all
the mathematical formulas included. Biologists
of that era seldom delved into mathematics. After
years of neglect, Mendel’s work was rediscovered
POINTING in 1900. Several scientists, working independently,
OUT
confirmed what Mendel had written. Today, he is
known as the “father of genetics.”
GREGOR MENDEL
Gregor Mendel grew up on a farm. He was a good By then, other scientists had made related and
student who wanted to attend the best schools in the important discoveries. Just three years after Mendel
region. But his family couldn’t afford it. He joined a published his paper, Swiss biochemist Johann
monastery instead. The leader of the monastery sent Friedrich Miescher made a startling discovery.
Mendel to the University of Vienna. That allowed
him to learn as much as possible about math and His subject was far different from Mendel’s peas.
science, his favorite subjects. When he returned to Miescher collected discarded, pus-filled bandages
the monastery, he began teaching at a local school. from patients with serious infections. Washing
But Mendel wanted to make a name for himself. off the pus, he was able to study lymphoid (white
He began his studies with pea plants. In later life, he
became the head of his monastery. blood) cells. He found a large, previously unknown
molecule in the nucleus, or center, of the white
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