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notes that, after mapping the human genome, researchers wondered
how so few genes could account for so much diversity among the
species.
-
recounts how one scientist determined how the deletion of a key
sequence of DNA on human chromosome 15 could lead to two
different syndromes depending on whether the deletion originated
from the mother or the father.
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explains that this was the first human evidence that something
other than genes themselves could determine how genes are
expressed.
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provides an animation of two ways that scientists think the
epigenome works to turn genes on and off.
-
cites differentiation as an example of the epigenome at
work—during development, cells switch on or off to
differentiate cell function; as the cells divide they retain a
memory of their cell type.
-
notes that while the epigenome is normally incredibly stable,
epigenetic switches sometimes can be thrown and later lead to
disease.
-
looks at how the epigenetic profiles of two 66-year-old twins
are very different from that of two 6-year-old twins, suggesting
that epigenetic changes accumulate over time.
-
presents several experiments with rats that reveal how the
epigenome works in an animal model.
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reports how epigenetic changes may promote disease by silencing
tumor suppressor genes or activating oncogenes.
-
reviews a clinical trial in which half the patients recovered
after being treated with a drug designed to remove chemical tags
silencing tumor suppressor genes.
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presents the work of two scientists looking for an epigenetic
influence on autism.
-
reports on a review of generations of historical records from a
remote Swedish village that suggests epigenetic changes may be
passed down through the generations.
NOVA explores how the epigenome—the body's complex chemical
network that controls gene expression—plays a role in human
biological destiny.
