"If you breed a stallion and a mare ..and they produce a dwarf..(so you know they both carriers, right?)"
Yes
"than you breed the stallion to ANOTHER mare and have a normal foal..what is the precentage possibility that the offspring is a carrier? Thanks "
Depends on if the mother to the normal foal is a carrier. If the mother to normal foal is a carrier then the foal has a 67% (2/3) that the foal is a carrier and 33% (1/3) chance the foal is homozygous normal.
I hope you understand that if the foal is NOT a dwarf then you take out 25% of he chances you would before conception. So therefore your calculations on the foal being a carrier only involve the 75% that are normal looking.
Now if the mother is a non-carrier, then the foal has 50% (1/2) chance of it being a carrier, and 50% (1/2) chance of it being homozygous normal. Because if the mare is NOT a carrier, then you will never have adwarf with those two being croosed.
All of this assuming we are talking about only one type of dwarfism.
John
