Mendel hypothesized that the color alleles segregate from each other during meio
ID: 98801 • Letter: M
Question
Mendel hypothesized that the color alleles segregate from each other during meiosis and then combine randomly during fertilization. To test this hypothesis he crossed a bunch of heterozygous plants (Yy times Yy) and counted 858 peas (progeny) that resulted. Remember, in peas, yellow is dominant to green. a. Which phenotypes and how many of each type are expected in the progeny? b. Among the progeny Mendel counted 651 yellow peas and 207 green peas. Perform a chi-square analysis to determine if pea color is inherited as a single locus trait where meiosis and fertilization occur as expected (segregation and random fertilization). Attach a sheet of paper that shows your work for this problem. The chi-square formula and a chi-square table is given for you. What is the chi-square value? _____ What is the p-value? _____ c. Put in words what this p-value means.Explanation / Answer
Answer a): 643.5 Yellow and 214.5 Green
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y
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Yy
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3/4 are yellow and 1/4 are green
Means 75% are yellow and 25% are green,
So, 858 x 0.75 = 643.5 Yellow
And 858 x 0.25 = 214.5 Green
What is the chi-square value? Answer: 0.35
total = 651+207 = 858 so expected is (3/4)858 = 643.5
and (1/4)858 = 214.5
chi-square = (651-643.5)2 /643.5+ (207-214.5)2/214.5 = 0.3496
What is the p-value? Answer: 0.9-0.5
p Value description:
The p-value is the probability that the differences between the observed and expected values are due to chance. In this case, the small deviation that we obtained between our observed and the expected values has a 50-90% probability of being due to just chance. Therefore, we can say that our observed values match our expected and pea color is inherited as a single locus trait where meiosis and fertilization occur as expected.
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YY
Yy
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yy