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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:
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). details
one epigenetic mechanism by which methyl groups attach to the histones,
affecting the expression of the DNA's genetic code. 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. 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. reports
on studies of identical (human) twins that reveal a measurable accumulation of
epigenetic changes as the twins age. 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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