You have isolated a new single gene mutation in zebrafish you call Casper because the mutant fish are clear (no pigments in the scales). You perform the following crosses: Cross Progeny Wild type X Casper 20 clear, 19 normal Casper X Casper 21 clear, 10 normal a. You notice that each cross produced a similar number of clear offspring but different number of normal offspring. What is going on here