Fifty years after legendary scientists James Watson and Francis
Crick discovered the structure of DNA, researchers are still unlocking
And a new model
of the DNA molecule, designed by a biology professor at The University
of Southern Mississippi, is helping students join in that discovery.
To aid in the
understanding of genetic coding, Dr. Ray Scheetz has developed a
highly durable plastic DNA model that allows students to handle
interchangeable blocks, fitting them together to form the molecule's
familiar helix shape. This interaction, Scheetz said, makes a lasting
impression on students because of its strong visual component.
learn in high school that genetic code is contained in the order
of these things called bases," Scheetz said, grasping a colored
block from the model. "They come in four flavors - A, T, C
and G. Most of us just memorize this, but I wanted a model that
was intuitive, something students can snap together and say, 'Ah,
that's how that works!'"
of genetic code and the key molecule of heredity, DNA (deoxyribonucleic
acid) is twisted into packets and tucked into the nucleus of every
living cell. Its structure was discovered by British scientists
Watson and Crick in 1953, and since their discovery, DNA research
has grown exponentially.
that ever since molecular biologists have learned to manipulate
the sequences of DNA, they have attained the ability to "do
some pretty amazing things." Among the wonders is gene therapy.
can now cut the sequence out of DNA molecules and paste them on
another, like a word processor. That means the future of medicine
is going to see a lot of gene therapy, where you correct the defects
instead of taking expensive medicines.
very possible that it will get to the point where they can fix defective
sequences in DNA or even repair them," Scheetz said.
the last three years, Scheetz' instructional model has been tested
in freshmen biology labs at Southern Miss this semester, where it
has drawn a positive response from students.
18, a freshman biology major from Natchez, said she liked the way
the model allowed her to "see how DNA works."
about the structure and the sequences in the books, but something
like this helps it all make sense," Washington said.
with less durable models made from cheap materials, Scheetz set
out to design his model from quality components. So, he turned to
the university's polymer science department for help. Working from
3-D computer drawings of the model, researchers used a "rapid
prototyping machine" to make a metal mold overnight - the same
kind that would have taken six months to make using traditional
taught courses a long time and I'm familiar with the other models
on the market. Some of them look like Tinker toys, with beads representing
the atoms. If you're a chemist you can recognize this, but if you're
a student, you can't make heads or tails of them," Scheetz
made at Excel Plastics in Hattiesburg, will be marketed to high
schools and other institutions this year. Southern Miss holds the
patent to the model and proceeds from it will go back into the biology
the blueprint for making all the proteins that make up who you are,"
Scheetz said. "They make things happen in cells, and make pigments,
or why you have brown hair or blue eyes. All the genetic traits
break down to protein activity, and DNA has the blueprint for that
encoded in its order.
a complicated molecule. But maybe this model, by allowing students
to handle it and figure out how it is all interconnected, can help
them better understand these building blocks of life."