To solve these problems, we need to analyze the observed phenotypes of the progeny and deduce the linkage arrangements and distances between the genes.
44. To determine the linkage arrangement of the three loci, we need to look at the phenotypes observed in the progeny:
- 259 hairless plants were observed, which means the hairless trait (h) is most likely not linked with the other two traits since it appears more frequently.
- 268 plants were anthocyaninless, jointless, and hairless.
- 40 plants were jointless and hairless.
- 941 plants were anthocyaninless and hairless.
- 931 plants were jointless.
- 32 plants were anthocyaninless.
From these observations, we can conclude that the anthocyaninless trait (a) and the jointless trait (j) are linked. The hairless trait (h) appears to be unlinked. Thus, the linkage arrangement is a-j, with h unlinked.
The correct answer is (a) h-a-j.
45. If the parental (P1) plants were homozygous, we need to look for a phenotype that appears in large numbers. From the observations, we see that 941 progeny were anthocyaninless and hairless. This is the largest number observed, so it is most likely the parental phenotype.
The correct answer is (c) anthocyaninless, hairless.
46. To estimate the distance between the anthocyaninless (a) and hairless (h) genes, we need to identify the progeny that have both traits and calculate their percentage among all progeny. From the observations, 268 progeny were anthocyaninless, jointless, and hairless.
% recombinant = (268 / 3000) * 100 = 8.93%
The correct answer is approximately (a) 20.0.
47. To estimate the distance between the anthocyaninless (a) and jointless (j) genes, we need to identify the progeny that have both traits and calculate their percentage among all progeny. From the observations, 268 progeny were anthocyaninless, jointless, and hairless.
% recombinant = (268 / 3000) * 100 = 8.93%
The correct answer is approximately (a) 20.0.
48. To estimate the distance between the hairless (h) and jointless (j) genes, we need to identify the progeny that have both traits and calculate their percentage among all progeny. From the observations, 40 progeny were jointless and hairless.
% recombinant = (40 / 3000) * 100 = 1.33%
The correct answer is approximately (a) 20.0.
49. To calculate the coefficient of coincidence, we need to divide the observed double recombinant progeny by the expected double recombinant progeny.
Observed double recombinant progeny: 268 (found in 44)
Expected double recombinant progeny: (268 / 3000) * 32 = 2.845
Coefficient of coincidence = observed double recombinants / expected double recombinants
Coefficient of coincidence = 268 / 2.845 = 93.93
The correct answer is (e) irrelevant (the options provided do not include the correct value).
Note: The calculations above assume that all observed progeny are derived from single crossover events.
44. Three recessive genes in the tomato plant produce an absence of anthocyanin pigment (a),
hairless plants (h), and jointless fruit stems (j). Among 3,000 progeny from a trihybrid F1 that
was testcrossed, the phenotypes in figure 5 below were observed. What is the linkage
arrangement of these three loci?
259 hairless 268 anthocyaninless, jointless, hairless
40 jointless, hairless 941 anthocyaninless, hairless
931 jointless 32 anthocyaninless
260 normal 269 anthocyaninless, jointless
a. h-a-j. b. a-h-j. c. a-j-h. d. j-h-a. e. two of these choices.
45. Three recessive genes in the tomato plant produce an absence of anthocyanin pigment (a),
hairless plants (h), and jointless fruit stems (j). Among 3,000 progeny from a trihybrid F1 that
was testcrossed, the phenotypes in figure 5 above were observed. If the parentals (P1) were
homozygous, which of the following could have been a parental?
a. anthocyaninless. b. jointless. c. anthocyaninless, jointless.
d. hairless, jointless. e. hairless.
46. Three recessive genes in the tomato plant produce an absence of anthocyanin pigment (a),
hairless plants (h), and jointless fruit stems (j). Among 3,000 progeny from a trihybrid F1 that
was testcrossed, the phenotypes in figure 5 above were observed. What is your best estimate of
the anthocyaninless-hairless distance?
a. 20.0. b. 35.2. c. 37.6. d. 40.0. e. 60.0.
47. Three recessive genes in the tomato plant produce an absence of anthocyanin pigment (a),
hairless plants (h), and jointless fruit stems (j). Among 3,000 progeny from a trihybrid F1 that
was testcrossed, the phenotypes in figure 5 above were observed. What is your best estimate of
the anthocyaninless-jointless distance?
a. 20.0. b. 35.2. c. 37.6. d. 40.0. e. 60.0.
48. Three recessive genes in the tomato plant produce an absence of anthocyanin pigment (a),
hairless plants (h), and jointless fruit stems (j). Among 3,000 progeny from a trihybrid F1 that
was testcrossed, the phenotypes in figure 5 were observed. What is your best estimate of the
hairless-jointless distance?
a. 20.0. b. 35.2. c. 37.6. d. 40.0. e. 60.0.
49. Three recessive genes in the tomato plant produce an absence of anthocyanin pigment (a),
hairless plants (h), and jointless fruit stems (j). Among 3,000 progeny from a trihybrid F1 that
was testcrossed, the phenotypes in figure 5 were observed. Approximately what is the coefficient
of coincidence?
a. 0.4 b. 0.5 c. 0.6 d. 1.8 e. irrelevant
how do you solve these problems explain please
1 answer