You are given three homozygous strains of siamese fighting f

You are given three homozygous strains of siamese fighting fish with different phenotypes (blue, red #1, red #2). You make crosses, with the results shown below (reciprocal crosses give the same results).

    parents                              offspring

blue x red #1                        all green

blue x red #2                         ½ blue ½ green

green F1 x green F1            91 green 29 blue 42 red

What is the genotype of the original red #1 parent?

R/R; B/B

R/R; B/b

R/R; b/b

r/r; b/b

none of the above

Solution

R/R;B/B

Since there are only 2 alleles & three phenotypes (blue, red #1, & red #2), we must be dealing with incomplete dominance. So the red #1 parent is homozygous red (RR ) and blue (BB).