Albino...........?

Question

Why is the Albino gene fatal in horses?
(something I read on Wikipedia)

Answer 1

It is called a lethal recessive. Some argue it is a dominant allele but that show a lack of understanding of the real functions of dominant and recessive.

A dominant allele is not simply the one that shows up in the heterozygous (that is an old definition or one that laymen use). A dominant allele is one that contains a recipe for an enzyme that functions. In most cases this allele is the one that shows up in a heterozygous since the other allele (recipe) codes for a faulty enzyme. However in the case of the white horse the dominant allele code for an enzyme that creates a substance used in more than one location. The substance is produced if the horse has one allele for normal color and one for white, BUT not in sufficient quantities. Since the other uses of the substance are more important than hair color the product is used there first leaving little or none for hair color. Thus the horse is white if there is only one copy of the white allele and one of the color allele. However, if two allele for white are present then the horse dies because it lacks critical substances which control development. Thus the horse dies shortly after birth.

White can also be had by being homozygous Frame. But those horses generally lack the last few inches of the large intestine and die shortly after birth because they can not defecate. This is not the gene that wikipedia is talking about.

The albino breed does not bred true. In fact, roughly 25% of their offspring die of lethal recessive, 25% come out colored, and only 50% of their offspring are white when you cross two 'albino' horses.

And ruredy2 is not correct. Homozygous Frame causes the blind colon but lethal white is from the 'albino' breed.

Paint girl.

I use equinecolor.com for the basics. The albino horse registry (I believe their site and perhaps name has changed). Various textbooks and websites that I can not at present recall because the books are at school not here. The last time I looked into this was about a month or two ago, when someone else posted a question on albinism. Had to go back to the beginning then as everything changed. Now specifically what doesn't add up to what you have read?
Oh there is no such thing as an overo gene. Overo is a laymens term which refers to any non-tobiano paint. There are two known genes that fall into that category. Frame and Sabino. Sabino does not cause the lethal recessive. Only Frame and the 'albino' which is actually white not albino. Rereading your answer, the reason they are not matching is probably because you are speaking of a different gene. You are talking about paint horses but lethal white is actually not a paint gene it is found in the american albino horse registry and is a gene that causes a white horse when you have a heterozygous individual. That is where the discrepency is probably to be found.

Correction the percentages I quoted are for Ww (albino) horses bred to Ww horses. However many horses in the breed are actually cremellos, smoky creams, and a few double frames which do survive at times, there may even be a few maximum expression sabinos in there as well. All homozygous 'albino' horses abort, are still born, or die shortly after birth.

BTW It is a common mistake and even printed in some texts that Lethal White Syndrome is from the Frame gene. This is because of confusion over the 'albino' gene. It is now known that the two genes are separate and are given separate names. LWS is technically from albino while lethal frame is from the frame gene.

Answer 2

As far as i know the Albino gene isn't fatal I once knew a 24 year old albino horse and he was completely healthy.

Answer 3

Actualy albino isn't always fatal, if the foal is born with a WW gene then its deffenetyl either going to be absorbed in the uterus, or born albino, and die a few days later. on the other hand Ww is were the horse is albino but it isnt deadly.
I know if you breed two certain types of paint horses, and the foal turn albino, its going to die because its intestin is seperated from its colon CORRECT ME IF IM WRONG,i dont know much about horse genetics, but this is what i was tought.

Answer 4

I'm in no way and expert at horses! But my parents had some paint horses and a mare that was prego. It was albino baby and died within a day or two. We were told that when they are developing that they dont develop a colon. But like I said, not completely sure!

Answer 5

The Wkipedia is made by regular poeple, not normally experts.

The Albino gene isn't fatal! There is a whole BREED based around it! I beleive that it's called the American Albino, and was made after three foundation stallys, only one was Albino.

Answer 6

http://www.apha.com/breed/lethalwhites03.html

I think you're referring to Lethal White. This website should help you understand the disorder.

Many times a horse somebody calls white is actually a maximal sabino or a mature grey that has gone white over time. Another commonly mistaken for white is the cremello...with its pink pigment and pale eyes, it's often called albino or white by mistake.

Answer 7

ruredy2g is right. It is call Lethal White Syndrome. It is caused by two recessive genes coming together. Overo paints can have it as well as roans such as belgians. Albinoism is just a lack of color pigment in the hair which creates pink skin and no color in the hair.

Answer 8

i think you are talking about a genetic disease called (overo) lethal white syndrome. horses aren't really albino either, but i digress. LWS

Lethal white syndrome (LWS) is a common genetic disorder primarily associated with American Paint Horses. A foal with this syndrome is born all white or nearly all white and has a non-functioning colon. There currently is no successful treatment for the disease; such a foal typically dies within two weeks. Because the death is often painful, these horses are generally put down once identified. However, care should be taken to not jump to conclusions based on coat color alone; there are many genetic mechanisms that produce white foals that are not LWS-affected, and a white foal that appears ill may be treatable. The disease has a similar genetic pattern to Hirschsprung's disease in humans.[1]

Answer 9

Well first of all wikipedia is not a great source of info. People can edit that to whatever they want, they can say that a certain breed of horses can read peoples mids. SO DONT LISTEN TO WIKIPEDIA,


but anywho albino gene isnt fatal in horses.
as far as i know the other problems with albinos and TRUE whites are that they are basically prone to skin cancer because there is no pigments in thier skin to protect them from the UV rays.


hope this helps.

Answer 10

The albino gene is not fatal in horses. You (or wiki) may be confusing Lethal White Syndrome found in overo Paint horses with Albino-ism. They are not the same thing. There is a genetic test that can be done on any horse (esp. of Paint heritage) that will test for the lethal white gene. Lethal White Syndrome is when the foal is born completely white. Both parents must be genetic carriers of the disease. Along with being completely white they have what is called a "blind colon" which means that their digestive system/intestines do not connect with the rectum/anus.....therefore bringing a painful death to the foal. The foal otherwise seems normal, will eat/drink, but eventually succumb/die due to colic from the lack of ability to defecate. It is a horrible death.

Answer 11

The albino gene is also prone to mutations...such as blindness, or could be missing something