Organisms with the genotypes AABbCcDd and AaBbCcDd are crossed. What are the expected proportions of the following progeny?

a phenotype identical to either parent

Verified step by step guidance

1. Identify the genotypes of the parent organisms: AABbCcDd and AaBbCcDd.
2. Determine the possible gametes each parent can produce. For AABbCcDd, the gametes are ABCD, ABCd, ABcD, ABcd, AbCD, AbCd, AbcD, Abcd. For AaBbCcDd, the gametes are ABCD, ABCd, ABcD, ABcd, AbCD, AbCd, AbcD, Abcd, aBCD, aBCd, aBcD, aBcd, abCD, abCd, abcD, abcd.
3. Use a Punnett square or a probability method to determine the genotypes of the offspring. Consider each gene independently and then combine the probabilities.
4. Identify the phenotypes of the parents. The first parent (AABbCcDd) has the phenotype determined by the dominant alleles A, B, C, and D. The second parent (AaBbCcDd) also has the phenotype determined by the dominant alleles A, B, C, and D.
5. Calculate the probability of offspring having a phenotype identical to either parent by considering the combinations of alleles that result in the same dominant phenotype.

Key Concepts

Genotype and Phenotype

The genotype refers to the genetic makeup of an organism, represented by alleles (e.g., AABbCcDd). The phenotype is the observable physical or biochemical characteristics resulting from the genotype, influenced by both genetic and environmental factors. Understanding the relationship between genotype and phenotype is crucial for predicting the traits of offspring in genetic crosses.

Mendelian Inheritance

Mendelian inheritance describes the patterns of inheritance for traits controlled by single genes, as established by Gregor Mendel. Key principles include the segregation of alleles during gamete formation and independent assortment of genes located on different chromosomes. These principles help predict the expected ratios of phenotypes in progeny from genetic crosses.

Punnett Square

A Punnett square is a diagram used to predict the genotypes and phenotypes of offspring from a genetic cross. By organizing the possible gametes from each parent, it allows for the visualization of potential combinations and their probabilities. This tool is essential for calculating the expected proportions of progeny with specific traits, such as those identical to either parent.