Genetic rarity

[Jorge]

Let me see if I can find this news in English for the benefice of all but until then:

Astonishing Birth of a Spanish Mule:

http://www.elnuevodia.com/asombraelpart ... 22764.html

[Jorge]

Let’s wait and see if another news agency translates the article but until then here are several links in Spanish.

http://www.andaluciainformacion.es/port ... 170839&ht=

http://www.noticias24.com/actualidad/no ... n-embrion/

http://www.eluniversal.com.mx/notas/754133.html

[Jorge]

Hope this free hand translation may help understand the news.

Summing up: a female mule gave birth to a female product thanks to an embryonic extraction taken from a mare who had been covered by a donkey (burro) and then transferred to said female mule, something that had never been produced in Spain.
The mule is already feeding her daughter of chestnut color who has already been named “Milagros” (“Miracles”). The veterinary is trying to prove that these animals can produce more than one foal per year due to embryonic transferal.

[r3b3l]

Leaving experiments aside, there are some cases of mules that have been pregnant and foaled naturally...they represent a very very very little percentage but the possibility exists.

The thing I don't get is why the doctor says that this experiment shows that "valuable" horses can have more than a foal per year with this procedure. Its obvious. Its already being done in many horse breeds, so that mares can continue their sport/show life. If they were pregnant too, instead of eventing, you would have 2 babies out of the same mare that year: one foaled by her and one by the transferred mare.

I don't see the point of it besides the fact that the receptor of the embryo transfer is a mule.

[Jorge]

r3b3l,

I also asked myself the very same question on the term "valuable". It doesn't make sense to me either. Perhaps the word should be substituted by the more complete phrase "in certain cases with sterile animals one can reproduce two copies for added value". Perhaps the expression was incomplete --hmm. who knows!

[summerhorse]

I don't think the problem with mules is so much they can't carry a foal it is because of the abnormal number of chromosomes so their eggs and sperm are usually infertile. But their wombs and testicles are not affected by that I don't think. So I'm not exactly sure what the vet is trying to prove???

[r3b3l]

Exactly, mules have all organs ready to produce a foal, the problem is just getting them pregnant, something you avoid with the transfer so....???

[xfactor fan]

Oh, yes, mules have all the bits needed to create a foal. Just think, all male mules are gelded early for a reason.

Molly's come into heat, just like mares. And the problem is that they don't produce eggs with the correct chromosome count. Very rarely they produce an egg that is either mostly horse chromosomes, or mostly donkey chromosomes, AND are covered by a horse or donkey. The Roman saying "When a mule foals" is like our "Once in a blue moon". An event that can happen, but is very unlikely.

I suppose with modern reproductive technology it might be possible to create a fertile mule--or mule like animal, something with a stable combination of horse and donkey chromosomes.

[belambi]

My understanding is that ALL male mules would be sterile.. and most females.

[Jorge]

Not the same case but perhaps even better.
http://www.npr.org/templates/story/stor ... d=12260255
http://news.bbc.co.uk/2/hi/sci/tech/2290491.stm

[RiddleMeThis]

My understanding is that ALL male mules would be sterile.. and most females.

Nah it's the same percentage male and female. The 99% of all males are just gelded and the females are rarely spayed. So, when the rarity happens you only here of it being females because the males are gelded.

And while the female is sterile she could still carry a foal, just not have a foal thats genetically hers. The parts still work. Same with males. They can ejaculate/get "ready" just can't actually impregnate.

[xfactor fan]

Again, if someone with deep pockets and a very good fertility lab really wanted to create fertile horse donkey hybrids. The male mules have the same problem that the females do, un-equal chromosome count in the sperm. But just like the females, the will every once in a while a sperm could be produced that was either all horse, or all donkey, and be capable of fertilizing a female.

[Jorge]

If one clicks to the following site,

http://www.sandiegozoo.org/animalbytes/ ... horse.html

(then go to the "Quick Facts" column) there is a reference and description of a very ancient horse known as the "Przewalskina" (who is still among us today) with a different count of chromosomes. Curiously it can be crossed with our modern horses and still reproduce.