4. There is a population of alien dogs, species Dogus Cute-ee-us, that live on t

Question

4. There is a population of alien dogs, species Dogus Cute-ee-us, that live on the planet Woof. Their genomes and biology are amazingly identical to the genomes and biology of earth dogs. Consider a di-hybrid cross, where the first locus has alleles A and a, and second locus has alleles B and b. Each additional copy of either an A or B allele in the two-locus genotype increases the friendliness of the dog. Friendliness is measured by the Wilcoxon-Canus Amicus Diagnostic Scale (WCADS). There are five categories: 0 = Unfriendly/Loner (although not aggressive); 1 = Somewhat friendly/shy; 2 = Friendly; 3 = Very friendly; 4 = Maximally friendly. For example, an alien dog with a two-locus genotype of Aabb would have a Somewhat friendly/shy behavior, since there is one copy of A and zero copies of B, adding to a score of 1 for the WCADS. Similarly, an alien dog with a two-locus genotype of AaBB has a Very friendly behavior (one copy of A + two copies of B = three copies total of A or B). In the following mating: AaBb x AaBb, what is the expected ratio of Maximally friendly:Very friendly:Friendly:Somewhat friendly:Unfriendly alien dogs in the offspring, assuming the parents produce a very large litter?

A. 1:2:3:2:1

B. Question cannot be answered with the information given.

C. 1:4:6:4:1

D. 9:3:3:1

E. 0:1:1:1:0

5.For an X-linked recessive trait, if a female fly who is a carrier for the trait-allele is crossed with a male who does not show the trait, what proportion of the offspring will show the trait?

A. 0.75 B. 0.25 C. 1 D. 0.5 E. 0

Explanation / Answer

4). C. 1:4:6:4:1

Cross between AaBb x AaBb will have the offspring with the following genotypes.

AaBb* AaBb = AABB (1/16, maximally friendly), AABb (2/16, Very friendly), AaBB (2/16, very friendly), AaBb (4/16, friendly), AAbb (1/16, friendly), aaBb (2/16, somewhat friendly), Aabb (2/16, somewhat friendly), aaBB (1/16, friendly), aabb (1/16, unfriendly).

The expected ratio of Maximally friendly:Very friendly:Friendly:Somewhat friendly:Unfriendly alien dogs in the offspring = 1:4:6:4:1

Related Questions

Navigate

• Browse (All)
• Browse 4
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.