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Barbara McClintock:
A Public Radio Commentary
by Bill Hammack
Listen using RealAudio
This month the U.S. Postal Service debuts a new commemorative
stamp set celebrating four American scientists. Over the next
four weeks I'll share with you the achievement of each scientist.
I begin with the first stamp: Barbara McClintock.
No one knew more about a cob of corn than Barbara McClintock.
Each spring this scientist rose very early in the morning to
plant corn on Long Island Sound, carefully fertilizing each stock
throughout the summer, then harvesting them at the end of the
season. She spend the long, quiet winter months analyzing her
harvest. Unlike most scientists she worked completely alone, so
much so that if a visitor showed up in the afternoon she often
had to speak softly, saying she hadn't yet used her vocal cords
that day. She studied the color of the corn kernels, which
varied from dark to light. In the 1940s she noticed distinct and
regular patterns in the colors of the kernels. McClintock knew
that these patterns reflected the genetic make-up of the corn. A
set of genes controls the appearance of every plant and animal;
this is, of course, the genetic code that we use in DNA testing
to determine paternity or to solve crimes. So, McClintock
realized that the rapid change in the corn's appearance meant
something revolutionary: No longer were genes the fixed, stable
things always though by scientists, instead they could
spontaneously change.
She spent the next three years checking and double-checking her
results before she revealed to her colleagues the existence of
these "jumping genes."
What does McClintock's work mean for us today?
Her work led to greater understanding of human diseases. For
example, how jumping genes can pass on resistance to antibiotics,
or how they let African sleeping sickness evade the defenses of
the human immune system.
Her work was so far ahead of its time that only 40 years after
she did her ground breaking research did she receive a Nobel
Prize. At age 81 all she had to say was "Oh Dear" - and then she
walked out in to the brisk air of Long Island Sound and spent all
morning picking walnuts. She returned, dressed in her dungarees
and carrying tongs for grappling with the walnuts, to address the
press. "It might seem unfair," she said, "to reward a person for
having so much pleasure over the years, asking the maize plant
[as she called corn] to solve specific problems and then watching
its responses."
The world, though, is richer today because Barbara McClintock
hear what the corn said back.
Copyright 2005 William S. Hammack Enterprises
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