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(Problem 12a) Assume independent assortment and start with a typical heterozygou

ID: 216784 • Letter: #

Question

(Problem 12a) Assume independent assortment and start with a typical heterozygous F1 plant (A/a ; B/b). Which of the following 9:3:3:1 ratios and genotypic designations best represent the expected outcome? 9 (A/A ; B/–); 3 (A/–; b/b); 3 (a/a ; B/–); 1 (a/a ; b/b) 9 (A/–; B/B); 3 (A/–; b/b); 3 (a/a ; B/–); 1 (a/a ; b/b) 9 (A/a ; B/b); 3 (A/a ; b/b); 3 (a/a ; B/b); 1 (a/a ; b/b) 9 (A/–; B/–); 3 (A/–; b/b); 3 (a/a ; B/–); 1 (a/a ; b/b) 9 (A/A ; B/B); 3 (A/A ; b/b); 3 (a/a ; B/B); 1 (a/a ; b/b) (Problem 14) In a diploid organism of 2n = 10, assume that you can label all the centromeres derived from its female parent and all the centromeres derived from its male parent. When this organism produces gametes, how many male- and female-labeled centromere combinations are possible in the gametes? 1024 64 32 1,048,576 cannot be determined (Problem 13) The A locus and the D locus are so tightly linked that no recombination is ever observed between them. If Ad/Ad is crossed with aD/aD and the F1 is intercrossed, what phenotypes will be seen in the F2 and in what proportions? All AD All ad 1:2:1 AD:Ad:aD 1:2:1 Ad:aD:AD 1:2:1 Ad:AD:aD (Problem 18a) If A/A · B/B is crossed with a/a · b/b and the F1 is testcrossed, what percentage of the testcross progeny will be a/a · b/b if the two genes are unlinked? 25% 38% 45% 50% 62% (Problem 18b) If A/A · B/B is crossed with a/a · b/b and the F1 is testcrossed, what percentage of the testcross progeny will be a/a · b/b if the two genes are completely linked (no crossing over at all)? 25% 38% 45% 50% 62% (Problem 18c) If A/A · B/B is crossed with a/a · b/b and the F1 is testcrossed, what percentage of the testcross progeny will be a/a · b/b if the two genes are 10 m.u. apart? 25% 38% 45% 50% 62% (Problem 18d) If A/A · B/B is crossed with a/a · b/b and the F1 is testcrossed, what percentage of the testcross progeny will be a/a · b/b if the two genes are 24 m.u. apart? 25% 38% 45% 50% 62% (Problem 31a) In corn, a triple heterozygote was obtained carrying the mutant alleles s (shrunken), w (white aleurone), and y (waxy endosperm), all paired with their normal wild-type alleles. This triple heterozygote was testcrossed, and the progeny contained 116 shrunken, white; 4 fully wild type; 2538 shrunken; 601 shrunken, waxy; 626 white; 2708 white, waxy; 2 shrunken, white, waxy; and 113 waxy.

What is the correct linkage map? y (18.4 m.u.) w (3.5 m.u.) s y (3.5 m.u.) w (18.4 m.u.) s s (3.5 m.u.) y (18.4 m.u.) w w (18.4 m.u.) s (3.5 m.u.) y w(3.5 m.u.) s (18.4 m.u.) y (Problem 31c) In corn, a triple heterozygote was obtained carrying the mutant alleles s (shrunken), w (white aleurone), and y (waxy endosperm), all paired with their normal wild-type alleles. This triple heterozygote was testcrossed, and the progeny contained 116 shrunken, white; 4 fully wild type; 2538 shrunken; 601 shrunken, waxy; 626 white; 2708 white, waxy; 2 shrunken, white, waxy; and 113 waxy.

Calculate interference for this region of the chromosome. 0.14 0.27 0.86 0.97 (Problem 12a) Assume independent assortment and start with a typical heterozygous F1 plant (A/a ; B/b). Which of the following 9:3:3:1 ratios and genotypic designations best represent the expected outcome? 9 (A/A ; B/–); 3 (A/–; b/b); 3 (a/a ; B/–); 1 (a/a ; b/b) 9 (A/–; B/B); 3 (A/–; b/b); 3 (a/a ; B/–); 1 (a/a ; b/b) 9 (A/a ; B/b); 3 (A/a ; b/b); 3 (a/a ; B/b); 1 (a/a ; b/b) 9 (A/–; B/–); 3 (A/–; b/b); 3 (a/a ; B/–); 1 (a/a ; b/b) 9 (A/A ; B/B); 3 (A/A ; b/b); 3 (a/a ; B/B); 1 (a/a ; b/b)

Explanation / Answer

12. Option C is correct.

9 = A_B_

3 = A_bb

3 = aaB_

1 = aabb

13. Option E is correct.

Parental cross: Ad/Ad X aD/aD

F1 progeny: AdaD

F1 selfing: AdaD X AdaD

Gametes: Ad aD X Ad aD

F2 progeny: AdAd AdaD AdaD aaDD

14. Option A is correct.

Number of different possibilities = 2^10

= 1024

18. Option A is correct.

Parental cross: AABB X aabb

F1 progeny: AaBb

F1 test cross: AaBb X aabb

Gametes: AB Ab aB ab X ab

Progeny: AaBb Aabb aaBb aabb