Black skin color is dominant to pink skin color in pigs. Two heterozygous black pigs are crossed.
What is the probability that their offspring will have pink skin?

Verified step by step guidance

1. Step 1: Identify the genotypes of the parents. Since the black skin color is dominant and the pigs are heterozygous, their genotypes are Bb, where 'B' represents the dominant allele for black skin and 'b' represents the recessive allele for pink skin.
2. Step 2: Set up a Punnett square to determine the possible genotypes of the offspring. Place one parent's alleles (B and b) along the top of the square and the other parent's alleles (B and b) along the side.
3. Step 3: Fill in the Punnett square by combining the alleles from the top and side. The possible combinations are BB, Bb, Bb, and bb.
4. Step 4: Determine the phenotypes associated with each genotype. BB and Bb result in black skin (dominant trait), while bb results in pink skin (recessive trait).
5. Step 5: Calculate the probability of pink skin (bb genotype) by counting the number of bb combinations in the Punnett square and dividing by the total number of combinations (4).

Key Concepts

Dominant and Recessive Alleles

In genetics, alleles are different forms of a gene. A dominant allele masks the effect of a recessive allele when both are present. In this case, black skin color is dominant over pink skin color, meaning that only one copy of the black allele is needed for the pig to exhibit black skin.

Punnett Square

A Punnett square is a diagram used to predict the genetic outcomes of a cross between two organisms. By organizing the alleles of the parents, it allows for the visualization of possible genotypes and phenotypes of the offspring. For the cross of two heterozygous black pigs (Bb x Bb), the Punnett square helps determine the probability of each skin color in the offspring.

Genotype and Phenotype

The genotype refers to the genetic makeup of an organism, while the phenotype is the observable physical trait. In this scenario, the genotypes of the pigs (BB, Bb, or bb) will determine their phenotypes (black or pink skin). Understanding the relationship between genotype and phenotype is crucial for predicting the traits of the offspring.