Converting the colorless flower pigment precursor #1 to the yellow colored pigme
ID: 53500 • Letter: C
Question
Converting the colorless flower pigment precursor #1 to the yellow colored pigment #2 is by either of single enzyme two pathways (colorless precursor #1 can be converted to yellow pigment #2 independently by either enzyme A or enzyme B). The first pathway is encoded by locus A (alleles “A” for functional and “a” for the inactive recessive) and the alternative second pathway by locus B (again “B” is the wt functional allele and “b” is the nonfunctional recessive allele). A cross of an AABB plant with an aabb plant gives an F1 generation all with yellow flowers. The expected ratio of yellow to white plants in the F2 generation would be:
3:1.
1:3.
9:7.
15:1.
12:4.
An “AA” individual is crossed with an individual with an “aa” genotype. The F1 offspring include 75% of the dominant phenotype (A) and 25% of the recessive phenotype (a). This could be a good example of:
incomplete dominance.
codominance.
simple dominant/recessive alleles.
epistasis.
partial penetrance.
Explanation / Answer
For First question answer is: 15 : 1
For second question answer: partial penetrance