Ch 3 35 35 Problem 33a part 1 In cucumbers dull fruit D is d

Ch. 3 35>>>>

Solution

(Problem 33a, part 1) In cucumbers, dull fruit (D) is dominant over glossy fruit (d), orange fruit (R) is dominant over cream fruit (r), and bitter cotyledons (B) are dominant over nonbitter cotyledons (b). The three characters are encoded by genes located on different pairs of chromosomes. A plant homozygous for dull, orange fruit and bitter cotyledons is crossed with a plant that has glossy, cream fruit and nonbitter cotyledons. The F₁ are intercrossed to produce the F₂. Give the expected proportions of offspring with a dull, orange, and bitter phenotype in the F₂.

for F1 generation are intercrossed = DdRrBb * DdRrBb

so we know for the 1st locus 3/4 dull(DD and Dd) ,, 1/4 glosy (dd)

for the 2nd locus 3/4 orange (RR and Rr),, 1/4 creamy (rr)

for the 3rd locus 3/4 bitter (BB and Bb),, 1/4 non bitter (bb)

so, answer: for the dull, orange and bitter,

3/4 dull * 3/4 orange * 3/4 bitter = 27/64 so answer is d) 27/64

(Problem 33a, part 2) In cucumbers, dull fruit (D) is dominant over glossy fruit (d), orange fruit (R) is dominant over cream fruit (r), and bitter cotyledons (B) are dominant over nonbitter cotyledons (b). The three characters are encoded by genes located on different pairs of chromosomes. A plant homozygous for dull, orange fruit and bitter cotyledons is crossed with a plant that has glossy, cream fruit and nonbitter cotyledons. The F₁ are intercrossed to produce the F₂. Give the expected proportions of offspring with a glossy, cream, nonbitter phenotype in the F₂.

so, answer: for the glossy, cream, nonbitter

1/4 glossy * 1/4 creamy * 1/4 nonbitter = 1/64

SO THE ANSWER WILL BE A) 1/64

(Problem 33a, part 3) In cucumbers, dull fruit (D) is dominant over glossy fruit (d), orange fruit (R) is dominant over cream fruit (r), and bitter cotyledons (B) are dominant over nonbitter cotyledons (b). The three characters are encoded by genes located on different pairs of chromosomes. A plant homozygous for dull, orange fruit and bitter cotyledons is crossed with a plant that has glossy, cream fruit and nonbitter cotyledons. The F₁ are intercrossed to produce the F₂. Give the expected proportion of offspring with a dull, orange, and bitter phenotype or a glossy, orange, and bitter phenotype in the F₂.

SO ANSWER : for the a glossy, orange, and bitter phenotype = 1/4 glossy * 3/4orange * 3/4 bitter = 9/ 64

so the answer is b) 9/64

(Problem 33a, part 4) In cucumbers, dull fruit (D) is dominant over glossy fruit (d), orange fruit (R) is dominant over cream fruit (r), and bitter cotyledons (B) are dominant over nonbitter cotyledons (b). The three characters are encoded by genes located on different pairs of chromosomes. A plant homozygous for dull, orange fruit and bitter cotyledons is crossed with a plant that has glossy, cream fruit and nonbitter cotyledons. An F₁ plant is crossed with a plant that has glossy, cream fruit and nonbitter cotyledons. Give the expected proportions among the progeny of this cross with a glossy, cream, bitter phenotype.

so answer : for the cross with a glossy, cream, bitter phenotype:

1/4 glossy * 1/4 cream * 3/4 bitter = 3/64

so the answer will be A) 3/64

**** question 39 and 40 pedigree is not given so question is incomplete..