An organism having the genotype AaBbCcDdEe is self-fertilized. Assuming the five genes assort independently, determine the following proportions:


Progeny that are expected to have a phenotype identical to that of the parent.

Verified step by step guidance

1. Identify the genotype of the parent organism: AaBbCcDdEe. Each gene pair represents a heterozygous condition, meaning the parent has one dominant allele and one recessive allele for each gene.
2. Determine the phenotype of the parent. Since the problem does not specify whether the dominant or recessive allele determines the phenotype, assume that the dominant allele contributes to the phenotype for each gene. Thus, the parent’s phenotype is determined by the dominant alleles: A, B, C, D, and E.
3. For the progeny to have a phenotype identical to the parent, they must inherit at least one dominant allele for each gene (A, B, C, D, and E). This means the progeny must have at least one dominant allele (A or aA, B or bB, etc.) for all five genes.
4. Calculate the probability of inheriting at least one dominant allele for each gene. For a heterozygous parent (e.g., Aa), the probability of passing on a dominant allele (A) is 3/4 when self-fertilized. This is because the possible genotypes for each gene in the progeny are 1/4 AA, 1/2 Aa, and 1/4 aa, and the first two contribute to the dominant phenotype.
5. Multiply the probabilities for all five genes to determine the overall proportion of progeny with the same phenotype as the parent. Since the genes assort independently, the combined probability is the product of the individual probabilities: (3/4) × (3/4) × (3/4) × (3/4) × (3/4).

Key Concepts

Independent Assortment

Independent assortment is a fundamental principle of genetics stating that alleles for different genes segregate independently of one another during gamete formation. This means that the inheritance of one trait will not affect the inheritance of another, allowing for a variety of combinations in the offspring's genotype.

Genotype and Phenotype

The genotype refers to the genetic makeup of an organism, represented by the alleles it possesses, while the phenotype is the observable expression of those genes, influenced by both genotype and environmental factors. In this case, the phenotype of the progeny will depend on the combinations of alleles inherited from the self-fertilized parent.

Punnett Square

A Punnett square is a diagram used to predict the genotypes and phenotypes of offspring from a genetic cross. By laying out the possible gametes from each parent, it allows for the visualization of the probability of each genotype occurring in the progeny, which is essential for determining the expected proportions of phenotypes in this self-fertilization scenario.