Suppose that the "fabulous" phenotype is controlled by two genes, A and B, as shown in the diagram below. Allele A produces enou
gh enzyme 1 to convert "plain" to "smashing." Allele a produces no enzyme 1. Allele B produces enough enzyme 2 to convert "smashing" to "fabulous." Allele b produces no enzyme 2. The A and B genes are both autosomal and assort independently. A true-breeding "fabulous" father and a true-breeding "plain" mother (aa bb) mate. What will be the expected ratio of the F_2 offspring from the F_1 generation? 9 "fabulous" 7 "plain" 13 "fabulous" 3 "plain" 9 "fabulous": 3 "smashing": 4 "plain" 12 "plain" 3 "fabulous" 1 "smashing" 15 "fabulous": 1 "smashing"
1 answer:
Answer:
The expected ratio of the F_2 generation from F_1 generation will be
<u>9 "fabulous": 3 "smashing": 4 "plain" </u>
Explanation:
The expression of the phenotype will follow Mendel's Dihybrid cross.
plain→smashing
(only when allele A is present, which produces Enzyme 1)
smashing→fabulous
(only when allele B is present, which produces Enzyme 2)
Keeping the above statements in mind, in F_2 generation, only the genotypes having both A and B alleles will express phenotype "fabulous",as both Enzyme 1 and Enzyme 2 are required for that. The genotype having at-least one A allele and no B allele will produce the phenotype "smashing", as Enzyme 1,produced by allele A, will convert "plain" into "smashing". Hence, the dihybrid cross will as in the attachment.
You might be interested in
Answer: 1). A and B are both dominant (because A and B are codominant to one another)
2). E. All of the above
Explanation:
1). From the image above, A and B are both dominant because they are equally expressed when they occur in a pair (when they occur as blood type AB), also they are dominant because each of them expressed itself when it occurs in a pair with a recessive allele (IAi and IBi).
2). The children of a father with A blood and a mother with B blood will have all the four blood types: A, B, AB, and O. If each parent has a recessive allele, that is if each parent is heterozygous for his/her blood type (IAi for the father and IBi for the mother), the cross between them will produce all the four possible blood types.
See the attached punnet square for more information.
