Genotype and Phenotype Ratios in Genetic Crosses
What is the expected genotype ratio and phenotype ratio for the cross Aabb x aaBb?
a. What are the possible gamete genotypes that each parent can produce?
b. What is the expected genotype ratio?
c. What is the expected phenotype ratio?
Expected Genotype and Phenotype Ratios for Aabb x aaBb Cross:
Expected genotype ratio:1 AaBb : 1 Aabb : 1 aaBb : 1 aabb
Expected phenotype ratio:1 dominant phenotype : 1 recessive phenotype
In a genetic cross between Aabb and aaBb, the expected genotype ratio can be determined by considering the possible combinations of alleles from each parent.
The genotype of the first parent, Aabb, can produce gametes with the alleles AB and ab. The genotype of the second parent, aaBb, can produce gametes with the alleles aB and ab.
By combining the possible gametes from each parent, we can determine the expected genotypes of the offspring, which are AaBb, Aabb, aaBb, and aabb. Each genotype has an equal chance of occurring, resulting in an expected genotype ratio of 1 AaBb : 1 Aabb : 1 aaBb : 1 aabb.
The expected phenotype ratio is determined by the presence of dominant and recessive alleles. In this cross, the dominant phenotype is expressed by the dominant alleles A and B, while the recessive phenotype is expressed by the recessive alleles a and b. Since each genotype has an equal chance of occurring, the expected phenotype ratio is 1 dominant phenotype : 1 recessive phenotype.