From:
Sukie Crandall
Date: 2010-03-23 01:50:55 UTC
Subject: [ferrethealth] Nova: Ghost in Your Genes
To: fhl <ferrethealth@yahoogroups.com>, Ferret Mailing List <ferret-l@LISTSERV.FERRETMAILINGLIST.ORG>, fg <Ferret-genetics@yahoogroups.com>
http://www.pbs.org/wgbh/nova/genes/
Full transcript:
http://www.pbs.org/wgbh/nova/transcripts/3413_genes.html
Although told mostly from a human perspective this Public Broadcasting
program applies to all living things, including ferrets. Some of the
things mentioned can be human specific but the TYPES of changes
and mechanisms seen may well appear more widely, even if they
are expressed differently.
So here are a few notes that I took:
The program began with identical twins, one of whom is autistic (later
getting
into epigenetic differences), and other identical twins with
differences such
as ones where only one gets a malignancy and the other continues to
remain
fine.
Then it explains what epigenetic is: That there are proteins
overlying the genome
and if those proteins are tightly bound then the genes can not express
themselves.
Epi means "above" and genome is obvious.
The genetics are the same from tissue to tissue and can change over
time, but not
a huge amount usually by reproductive years. On the other hand, the
epigenome
is how the genes communicate with the outside world and the epigenome
varies
from tissue type to tissue type, varies among environments, varies
across time in
the individual, and can even affect later generations and often not in
good ways.
We've all read about agouti mice and soy, how giving a soy compound
during
pregnancy results in offspring who are thinner, darker in fur, and far
less prone to
diabetes and heart disease. Those study results have been replicated
by giving
sufficient B-12 and Folic Acid to pregnant mice, with healthier
offspring that way, too.
BUT, don't take that to mean that hefty nutrition during pregnancy is
good and you
will see why a little later. It should be the right nutrition but not
overdone.
Then they went into how malignancy happen more with old cells because
the more
replications that occur the older the cells are, and the more chance
there is for
mistakes to creep in with each replications, then mentioned that since
malignant
cells are constantly replicating without control they are downright
ancient. The more
they replicate the worse they get in changes.
Some locations can suppress malignancies. We've all read about those
on the FHL
and elsewhere. Some of those genetic locations need to be turned off
to have the
suppressant effect. The program next went on to show "Diplomacy"
treatment of
a malignancy that had been untreatable. It is an epigenetic treatment
which is not
a cure but a control approach.
To illustrate one case in which environment molded the epigenome and
that effect
was passed down through generations they went into a study of diabetes
and
mortality rates in people in a location which had experienced famine
in the grandparents'
generation. The effect was only carried down the paternal line to the
current generation
but they do not know why. On the female side the effect happened as a
fetus and in their
case the ones who experienced famine as fetuses had grandchildren who
died earlier.
The paternal grandfather, though, had a different situation. If the
paternal grandfather
was well fed at about age 10 (late childhood in general) then the
grandchildren of that male
were dramatically more likely to develop diabetes or to die early, or
both.
Eggs begin development earlier than sperm which may be why the age
difference shows
up.
*****
Now, many hypotheses involving insulinoma in ferrets have been derived
from diabetes
work or diabetes hypotheses in other animals. Is there a possibility
that allowing
breeder ferrets to be TOO well nourished or even obese is setting up
later generations
for insulinoma through an epigenetic mechanism similar to the one
where the grandparents'
nutrient exposure (fetal for females, mid to late kithood for males if
the timing pattern is
the same for ferrets)
*****
In another rodent study fetal pesticide exposure was found to cause
epigenetic changes
what appeared in 85% of the animals for every generation afterward
that they traced it
(many generations). This is in keeping with some current studies on
things like fetal
exposure to cigarette smoke which appears to relate to some health
problems for many
generations afterward.
Although ferrets were never mentioned the mechanisms are the same,
and since the
proportions and rates of some ferret diseases are so different now
than they were 20
years ago, and one thing documented in a different species (ours) is
that can have
an epigenetic trigger in a grandparent is endocrinological (diabetes)
then perhaps
perhaps it makes sense to try to figure what things may be done, not
only in current
generations but in previous ones, which may at least "help" set up our
ferrets for certain
diseases, and maybe it really makes sense to avoid ferrets who as
kits, or as fetuses
were around things like second-hand smoke, or whose parents or
grandparents were,
and to avoid breeding any male ferrets who were over-nourished (chubs)
during kithood.
Sukie (not a vet)
Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/
http://www.ferrethealth.msu.edu/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
all ferret topics:
http://listserv.ferretmailinglist.org/archives/ferret-search.html
"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)
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