Question

Dr. Cripps and Dr. Facette are carrying out genetics experiments using dust bunnies. Dr. Cripps has two female brown dust bunnies, Fluffy and Twinkle. Dr. Facette has one grey male dust bunny, Thor. When Fluffy and Thor were mated, all six offspring were brown. When Twinkle and Thor were crossed, five of the offspring were brown, and four of the offspring were grey. a. Use genetic symbols to explain these results, and indicate how many genes and alleles control coat colour. Which trait is dominant and which is recessive? 0.5 pts b. For each of the parents, give their genotypes. 1.5 pts

Answer 1

Based on the above information one gene with two alleles controls the skin color.

In the cross between Fluffy and Thor, the all brown indicates that the flyffy female is homozygous for brown condition and the brown appearence indicates that the Brown is dominant over grey.

In the cross between twinkle and Thor, the brown and grey indicates that the twinkle female is heterozygous for brown condition, so, the offspring brown and grey is in 1:1 ratio.

Find the below images for explanation and genotypes...