Inheritance

Question 1

Explain why there is a greater number than expected of the parental phenotypes.

OR

Explain deviation of observed test cross results from the expected dihybrid cross ratio.

Answer 1

1. The 2 genes for [trait] and [trait] are linked, and alleles of the 2 genes will be inherited together as 1 linkage group, resulting in a higher proportion of gametes carrying the parental types
2. Crossing over between the 2 linked genes on non-sister chromatids of homologous chromosomes is a chance event, resulting in a lower proportion of recombinant gametes
3. thus, observed offspring of test cross are majority of parental types and minority of recombinant types