Actually, Liriel's analysis of the situation where Pandie Ebony & Ivory is dominant to Pink & White No. 1 is correct, whether derived from the Punnet square, or the less visual version of calculating the conditional probability.
A conditional probability is the probability of an event occurring when a given condition exists, when the event and condition are not independent. In this case, it is the probability of a certain fur hiding given the condition that Pandie Ebony & Ivory is showing. In this case the event & condition are clearly not independent, since removing the condition that the Pandie is showing would change the calculation ( the possibility of Mom passing Oci Lav or better & Dad passing Pink & White or better would have to be included).
The solution would look like this:
There is a 3/4 chance of Pandie E+I showing in a breeding of the 2 parents involved (every case except P&W +/ Oci Lav+ would result in the Pandie showing).
There is a 1/4 chance of each of the following events:
Pandie E & I hiding Pandie E + I,
Pandie E & I hiding Oci Lav + and
Pandie E & I hiding P & W +.
I'll show the calculation for the last case (the other 2 calculations would be the same):
P(P&W+ hiding, given the condition that Pandie E & I is showing)= P(Pandie E & I hiding P&W +)/ P(Pandie E & I is showing)= (1/4)/(3/4)= 1/3.
For another example of an application of conditional probability to genetics, see example 2 on this page:
http://nitro.biosci.arizona.edu/courses/...ure16.html
Breeding Question
