Is overo the dominant color???

Question

I bought an Overo Paint mare in April and she was out to pasture with a gray stud. Just found out she is pregnant this morning!!! I am so excited! but i would like to know if her baby will be a paint and is that overo gene dominant. i would love a paint baby. but of course a healthy baby is my 1st priority. anyone know?

Answer 1

I believe paint mares are one of the most dominant horses you can get

Answer 2

There is no such thing as an 'overo' gene.  Overo is a term which refers to any non-tobiano paint.  Overos include both horses with Sabino (the most common gene which causes overo) and Frame which is less common and the culprit behind OLWS.  

Sabino is dominant.  If you mare has two genes for sabino (one from her mother and one from her father), then the offspring will be a paint.  If she has only one gene for sabino (a gene from one parent but a non paint gene from the other) then the offspring has a 50% chance.

Frame is the culprit behind OLWS.  If your mare had two genes for frame (one from each of her parents) she would have been born white.  Almost all of such young are born missing the last section of the large intestine and therefore can not defecate (p**p) so they die shortly after birth.  This is OLWS.

Therefore if your mare has a frame gene she would only have one and her young would have a 50% chance of being paint.

Edit I forgot that grey can cover or mask any other color.  So there is at least a 50% chance that your foal can wind up grey even if it is a paint.

Answer 3

Your mare is heterozygous for overo so she will pass it to 50% of her foals.

Grey can override any other colour so if the stud is heterozygous you have a 50:50 chance of grey but if he has the grey gene from each of his parents he may be homozygous which means all his offspring will be grey.

http://www.horse-genetics.com/

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