can someone tell me the percentage of a dog being optigen affected/carrier where the dog's grandsire is on the carrier list already published? much appreciated

Is everyone else clear?

If there are no other carriers in the pedigree, then the dog has a 25% chance of being a carrier. Probability of the grandparent passing it to the parent = .5. Probability of a parent passing thatgradparent's gene to the dog = .5. These are two independent events, so the probability of both happening is .5 X .5 = .25, or 25%

The best way to determine is to have the dog tested. We all know percentages. That recessive gene can sneak down several generations.

thank you to all for your explanations. your answers are much appreciated