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NOVA scienceNOW: Epigenetics
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Program Overview
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Scientists introduce epigenetics, the study of mechanisms
controlling gene expression that are independent of the DNA sequence
itself. Researchers examine the role epigenetic factors might play
in cell differentiation, cell development, disease, and heredity.
This NOVA scienceNOW segment:
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introduces epigenetics and notes a key difference between
genetics and epigenetics. Genetics is the study of DNA-based
inherited characteristics in organisms while epigenetics can
involve modifications to DNA (i.e., DNA methylation) or changes
to the structures surrounding the DNA (i.e., the chromatin's
histones).
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details one epigenetic mechanism by which methyl groups attach
to the histones, affecting the expression of the DNA's genetic
code.
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explains that chemicals that may have an epigenetic effect, such
as methyl groups, can enter the body from one's environment.
Consequently, an individual's choices and personal history, such
as diet and smoking, can influence his or her exposure to
epigenetic triggers and their accumulation in the body.
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describes studies that demonstrate the effect of epigenetic
factors. For example, one set of genetically identical mice was
fed food rich in methyl groups. The methyl groups bonded to the
mice's chromatin and blocked the expression of certain genes.
This epigenetic effect produced two sets of mice that looked
extremely different.
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reports on studies of identical (human) twins that reveal a
measurable accumulation of epigenetic changes as the twins age.
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notes the development of a promising line of therapies that work
by rearranging a cell's epigenetic tags. One epigenetic therapy
mentioned attempts to alter the behavior of cancer cells.
Taping Rights: Can be used up to one year after the program
is taped off the air.
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