Phenotypic Distribution in Dihybrid Cross with Linked Loci

In a dihybrid cross with linked loci, two heterozygous parents are crossed to analyze the inheritance of two different traits. Linked loci are located close together on the same chromosome, which results in the two traits being inherited together more often than expected by independent assortment.

Explanation:
- When two heterozygous parents with linked loci are crossed, the parental genotypes are AaBb x AaBb.
- Due to linkage, the two traits will tend to be inherited together, resulting in a different phenotypic distribution than expected for unlinked loci.
- The recombinant phenotypes will be less frequent than the parental phenotypes because crossing over events between the linked loci are rare.
- The phenotypic ratio in the offspring will show more of the parental combinations and fewer of the recombinant combinations.

Phenotypic Distribution:
- The phenotypic ratio in the offspring of a dihybrid cross with linked loci will typically show a higher frequency of the parental phenotypes (AB and ab) compared to the recombinant phenotypes (Ab and aB).
- The actual distribution will depend on the distance between the linked loci and the frequency of crossing over events during meiosis.
- If the linked loci are very close together, the parental phenotypes will be predominant in the offspring.
- As the distance between the linked loci increases, the frequency of recombinant phenotypes will also increase.

In conclusion, in a dihybrid cross with linked loci, the phenotypic distribution in the offspring will deviate from the 9:3:3:1 ratio expected for unlinked loci, with a higher frequency of parental phenotypes and a lower frequency of recombinant phenotypes due to linkage.