For the cross BB×Bb, what is the expected genotype ratio? What is the expected phenotype ratio?

Verified step by step guidance

1. Step 1: Identify the genotypes of the parents in the cross. In this case, one parent is homozygous dominant (BB) and the other is heterozygous (Bb).
2. Step 2: Set up a Punnett square to determine the possible combinations of alleles. Place the alleles of one parent (BB) along the top and the alleles of the other parent (Bb) along the side.
3. Step 3: Fill in the Punnett square by combining the alleles from the top and the side for each box. This will give you the possible genotypes of the offspring.
4. Step 4: Count the frequency of each genotype in the Punnett square. For example, determine how many offspring are BB and how many are Bb.
5. Step 5: Determine the phenotype ratio by considering the dominant and recessive traits. Since B is dominant, both BB and Bb will express the dominant phenotype. Calculate the ratio of dominant to recessive phenotypes based on the genotypes.

Key Concepts

Genotype

Genotype refers to the genetic constitution of an organism, specifically the alleles it possesses for a particular gene. In the context of the cross BB×Bb, the genotypes involved are homozygous dominant (BB) and heterozygous (Bb). Understanding genotype is crucial for predicting the genetic outcomes of crosses.

Phenotype

Phenotype is the observable physical or biochemical characteristics of an organism, determined by both its genotype and environmental influences. In this case, the phenotype ratio will depend on the dominant and recessive traits expressed by the genotypes BB and Bb. Recognizing the relationship between genotype and phenotype is essential for interpreting the results of genetic crosses.

Punnett Square

A Punnett Square is a diagram used to predict the genotypic and phenotypic ratios of offspring from a genetic cross. By arranging the alleles of the parents (BB and Bb) in a grid, one can easily visualize the possible combinations and their frequencies. This tool is fundamental for understanding inheritance patterns and calculating expected ratios in genetic crosses.