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Science and Technology
1950s
The Mystery of DNA
If you have ever wondered why you have brown skin or curly hair
you have only to look to your biological parents for answers. When
you were conceived, cells from the male and female united to form
a new organism. Within each of those cells are thin threads called
chromosomes which are made up of DNA (deoxyribonucleic acid).
Part of these cells are genes. It is the genes which tell your body
how to develop. Genes carry coded information about the
characteristics of the parents, like the size and shape of the nose, or
whether a person is right or left-handed.
Although genes had been identified as early as the 1800s by
Austrian monk Gregor Mendel, it was not known what the genes
were composed of or how they worked. It was not until 1944 that
scientists discovered that the DNA contained in the chromosomes
carried the genetic message. During the 1950s a team of scientists,
Watson and Crick, was able to build a model of the DNA molecule.
Each molecule consists of millions of atoms arranged in a double
helix (spiral shape) held together by cross pieces (see diagram).
The order in which the atoms are arranged determines the code of
genetic information which is then passed on to the next generation.
Today, scientists have developed a technique called genetic fingerprinting, which can be used to track
criminals and study diseases. Also in the experimental stages is genetic engineering which will offer a
method for altering the genes and thus changing the characteristics of an organism.
——————————— Suggested Activities ———————————
Activity On the lines below make a list of at least 30 physical and personality characteristics
that are determined by genes. Be specific, i.e. foot size, shape of a mole, etc., rather than
general: looks, personality.
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