Now there is a discipline that has evolved
in recent years called epigenetics.
And epigenetics is absolutely fascinating; because,
what it says is that some
traits can be transmitted
across generation and these
traits are not encoded in the DNA.
And for people 20 years ago that was almost
heresy. But now we know that there is, in fact,
this phenomenon as epigenetics.
And this phenomenon of epigenetics
has a basis in what we have
been talking about here.
So, imagine that I chemically
modify one of the histones.
And in chemically modifying that histone
that chemical modification carries
across to the next generation.
That in fact can happen. That's transmitted across
generation. Well, what if that modification
in the original histone was a result
of the action that the person
who contained that histone
had. So for example, a really good example,
if your grandmother was
and you are a male,
interestingly enough that information can be
transmitted to you. It becomes much more likely
that you, as a result of that, experience of
your grandmother will be overweight.
So that information was encoded
in the proteins that control
the desire to eat for example.
Your grandma was nutritionally deficient
it got transmitted through to you and that
her DNA wasn't any different than
your DNA was with respect to those genes.
However, the chemical modification
of those histones carried forward.
That's known as epigenetics and there
are many examples we know up today.
So these transcriptional
affects can be transmitted
and have nothing to do with a change in
the sequence of the DNA. But rather have to do
with these carried forward
modifications of the histones.
These influences, as I said, are called epigenetics
meaning that they are beyond the genetics
that are there and the
genetics are the DNA.