In mussels brown (B) coloring is dominant and blue (b) coloring is recessive. If a blue mussel has two brown parents what percentage of the total offspring of these brown parents are expected to be bl?

If both brown parent mussels are heterozygous (Bb), then they can pass on either the brown (B) or blue (b) allele. The possible combinations for their offspring would be BB, Bb, and Bb, resulting in a 75% chance of brown offspring and a 25% chance of blue offspring. Since the blue mussel (bb) is a recessive phenotype, it cannot arise from two brown parents unless both are carriers of the blue allele. Therefore, if both brown parents are Bb, 50% of the offspring would be expected to be Bb (brown) and 25% would be bb (blue). Thus, 25% of the total offspring are expected to be blue (bb).