Question

In beta fish, green fish have the genotype CC, dark blue fish have the genotype cc, and green and blue spotted fish have genotype Cc.Two green and blue spotted beta fish are crossed. What percentage of the offspring is expected to be green?

Answer 1

Answer: 25%

Step-by-step explanation:

Answer 2

25%

Step-by-step explanation:

This cross involves a single gene coding for spot color in beta fish. Green allele is C while the blue allele is c. This gene exhibits co-dominance, hence, an heterozygote beta fish (Cc) i.e. combination of both alleles, will have both phenotypes expressed to form a green and blue spotted beta fish.

If two green and blue spotted beta fishes (Cc) are crossed, each beta fish will produce gametes with C and c alleles. Using these gametes in a punnet square, four possible offsprings with the following genotypes will be produced: CC, Cc, Cc and cc.

C c

C CC Cc

c Cc cc

Hence, the percentage of offsprings expected to be green (CC genotype) is 1 out of 4possible offsprings i.e. 1/4 × 100 = 25%