What is the expected phenotype ratio for a dihybrid cross producing linked genes?

In the context of a dihybrid cross involving linked genes, the expected phenotype ratio when the two genes are on the same chromosome and inherited together may not align with traditional Mendelian ratios, which are typically assumed for unlinked genes.

However, the common expectation for a dihybrid cross involving unlinked genes is a ratio of 9:3:3:1, reflecting the independent assortment of two traits where each trait has two alleles contributing to phenotype expression. This 9:3:3:1 ratio arises from considering all possible combinations of alleles from the two parents.

When a cross involves linked genes, the phenotypic ratios can still yield the 9:3:3:1 ratio under certain circumstances, particularly in the case of incomplete linkage, where crossing over can still occur, allowing for some recombinant phenotypes to appear. If the genes are completely linked, you would not observe the full 9:3:3:1 ratio but rather a skewing towards parental phenotypes.

In this case, the choice indicating a 9:3:3:1 ratio is often considered as the standard outcome for a dihybrid cross under normal circumstances without genetic linkage being accounted for in detail. This choice reflects