My server is kind of wacky lately--they are adding new lines n' stuff, so
some of my mail has been bounced.  If so, just ship it back.  I've been
getting the FML in weird sequences as well.  Ah, life...
 
Just a quick note on breeding practices.  There are two reasons/objections
to close-relative breeding.  The first is moral/religious/cultural, and the
other is the expression of "bad genes."
 
Most genes are of the dominant-recessive variety; some could care less and
always express themselves to one degree or another.  When a "bad gene" crops
up and is dominant, it is usually expressed.  If the gene doesn't kill the
individual, it is recognized, and usually the individual is not bred, ending
the transmission of the gene.  Recessive genes are a little more sneaky in
their approach.  Because they are not generally seen, the trait can survive
for quite a long time without ever being suspected; that is, until paired
with another recessive gene.
 
Close breeding increases the chance for the expression of recessive genes,
"good" or "bad." Virtually every domesticate, from mammals to plants, have
been closely bred at one time or another in their genetic history.  In many
cases, its the only way to insure the transmission of the desirable trait.
But it has risks, which are the expression of bad characteristics, a general
loss of robustness in the genetic line, and other complicated and technical
stuff.  While these are/can be nasty to the unfortunate individual, are they
bad to the species in general?  There are hundreds of cases where a bad
trait for the individual is a good trait for the species (Sickle-cell anemia
in humans is a perfect example.  While individuals expressing the recessive
trait die, those with the combination of recessive-dominant are resistant to
malaria.  There are hundreds of other examples in this vein.)
 
If you own a domesticated ferret, you are looking at the descendant of close
inbreeding.  If the ferret is albino, you can be absolutely sure, because
albinism is recessive.  In fact, most color schemes other than dark sable is
a result of the genetic manipulation of our beasties.  Is this normal?
 
No and Yes.  Not usually--nature tends to want as diverse a genetic code as
possible.  Variation is what drives natural selection .  But, in some cases,
there is very little genetic differences between individuals within a
population.  Usually, this is because a speciation event just took place, or
because the species is dying out; in both cases, there are limited numbers
of breeding pairs, which translates as close-breeding.  Is this desired?
 
In higher vertebrates, there is an olfactory response to siblings.  At
first, it helps maintain cooperation, lower aggression, etc.  Later, at
mating time, especially in females, it serves as a "hands-off" signal, and
helps to eliminate close-breeding.  It doesn't prevent it; just helps to
slow it down.  In domesticates, humans force the issue one way or another.
(there is some tenuous evidence that solitary animals, such as polecats,
only accept others because they consider them to be siblings.  In the
domesticated ferret (and most domesticates) the animals never really seem to
get past the juvenile stage; once they become accustomed to the smell of the
other ferrets, they treat them as siblings rather than competitors.  There
is considerable variation in this response.)
 
As for the MF thing, yes, lab breeders tend to want animals that respond
similarly, but they also want animals that are healthy and genetically
disease-free (You don't want to use a cancerous ferret to study the
carcinogenic effects of toxins, nor a sick ferret to study disease) Yes, I
have heard that some strains of ferrets are predisposed to specific cancers,
but since those types of animals (if purposely bred) command higher prices
and are in demand by medical labs, few would reach the pet market.  I have
no desire to argue the ethics of using one species to better the lives of
the same or other species.  Lets just say it happened, happens, and will
continue to happen.  I have 5 MF rescues, 5 from a local breeder, and 3 from
breeders unknown.  Of them, I suspect Foster and Buddy to have some genetic
problems (unknown breeder.  Ok, TLE, we know, but for all purposes, unknown)
due to inbreeding.  Still, Foster (AKA Booger) is 9 years old, robust,
healthy, loving, and plain aggressive to outside ferrets.  Buddy is not
quite as robust, is 7 years old, and the same in other respects.  They were
also neutered at a late age.  It is impossible to tell if late-neutering or
genetics has resulted in their "negative" traits.  (My SO says
late-neutering, because everyone knows testosterone is a toxic poison...)
What I'm saying is, just because it's marked MF, or they are closely-bred
doen't mean the result is bad, or than bad characteristics are genetic in
origin.
 
As for genetics and cancers, the environment has a profound influence on the
expression of most cancers.  I suspect many of the cancers expressed in our
little fur muffins are environmental rather necessarily of genetic origin.
As I'm sure most of our non-American readers would attest, we treat our
beasties a might different than in most countries, and certainly
historically, and changes in exposure to "apartment toxins", dietary
changes, biochemical changes caused by indoor confinement, even the
continual exposure to second-hand smoke, EM radiation, or molds have never
been ruled out as causitive agents for ferret cancers.  One should compare
the domesticate with the wild predecessor and eliminate lifeway and dietary
differences, then go after the genetics.
 
Bob and the 13 fur muffins
[Posted in FML issue 1472]