Endurance.Net Ridecamp Archives

> The Mitochondria, that are the energy factories in the cells, are almost
> exclusively from the  tail mare.
Actually, there isn't even much "almost" to it--the mitochondria from the
midpiece of the sperm are actively and specifically excluded from
penetrating the ovum by the ovum's cell wall.

> There are also other things that go through daughters, not sons.
> Scientific American had an article a few years ago "When greatness skips
> a generation" that followed this in TB's.  It was brought up because
> Secretariat was such a disappointing sire of fast horses.  I have
> noticed that he is starting to show up in fast TB pedigrees, but haven't
> looked to see if it his daughters that are responsible like was
> predicted in the article.
There are traits that are located on the X chromosome that fit this
pattern.  The sire passes on an X to his daughters but not to his sons. 
So if he is the carrier of a trait and it is mostly the males that are
being used in performance, then it will be his daughters' sons that will
inherit the traits.

This is a whole different deal than the mitochondria, which can ONLY come
from the mare.

The link between the DNA in the mitochondria and the mitochondrial role in
energy metabolism is not entirely established, but can't help but believe
that there IS a link.  To bring the mitochondrial role in metabolism a
little closer to home for endurance riders, when we talk about horses
being able to use things like sugars and volatile fatty acids for energy,
ALL of that utilization goes on in the mitochondria of the cells.

Heidi


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Personally, I shouldn't give a s--- where the other people on the course
are, and if I find myself starting to concern myself over this, I remind
myself that this is the first step on the road to overriding my horse and
tell myself to "knock it off!"  :)
~  Kat Swigart

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