Incomplete genetic linkage of three genes in a trihybrid produces eight genetically different gamete genotypes. How many different gamete genotypes are produced in a four-gene cross with incomplete genetic linkage?
A)4
B)8
C)16
D)20
E)24

Question

Quizplus · Accepted Answer

For a four-gene cross with incomplete genetic linkage, we can use the formula 2^n to find the number of different gamete genotypes produced, where n is the number of independent assortment groups. For incomplete genetic linkage, each independent assortment group corresponds to a set of two genes that are not linked to each other but may be linked to genes in other independent groups.

In a trihybrid cross, there are three independent assortment groups, and we are given that there are eight genetically different gamete genotypes. This means that each independent assortment group produces two genetically different gamete genotypes.

For a four-gene cross, there are six possible independent assortment groups: ABC-D, ABD-C, ACD-B, BCD-A, AB-CD, and AC-BD. Each of these groups produces two genetically different gamete genotypes, so the total number of different gamete genotypes produced is 2^6 = 64. However, we need to consider that some of these gamete genotypes may be duplicates due to crossover events in different independent assortment groups. The actual number of different gamete genotypes produced will be less than 64, but it will still be greater than 8.

Therefore, the best choice for the number of different gamete genotypes produced in a four-gene cross with incomplete genetic linkage is C) 16.

Incomplete Genetic Linkage of Three Genes in a Trihybrid Produces