Ask A Scientist Molecular Biology Archive

name Aliya
status student
grade 9-12
location N/A

Question - What are homeotic genes and homeotic mutants?
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Homeotic genes are genes involved in developmental patterns and
sequences. For example, homeotic genes are involved in determining
where, when, and how body segments develop in flies. Alterations in
these genes cause changes in patterns of body parts, sometimes causing
dramatic effects such as legs growing in place of antennae or an extra
set of wings or, in the case of plants, flowers with abnormal numbers of
parts. An individual carrying an altered (mutant) version of a homeotic
gene is known as a homeotic mutant.

C. Perkins
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In your house you have a fuse box (or circuit breaker box). You can turn
off one or two breakers at once, or at the top of the box is a switch that
controls the whole house. In the embryo, there are certain genes that have
control over a whole group of other genes and the time at which they are
expressed. These are called homeobox or homeotic genes. All animals have
them and for the most part they are similar. They are the genes that lay out
the basic plan of the body. If they are mutated, they can change either the
way the body is laid out, or inactivate the genes that control a whole part
of the body. For example, snakes are reptiles by definition, but have no
limbs. Research shows that certain of the homeobox genes that control the
genes that control limb development are mutated.
For more information about this, view the video at this link:

http://www.pbs.org/wgbh/evolution/library/03/4/l_034_04.html

vanhoeck
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