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Homework Assignment #4 Questions
| Cross |
AaBb |
Aabb |
aaBb |
aabb |
Total |
| 1 |
310 |
287 |
288 |
315 |
1200 |
| 2 |
36 |
23 |
23 |
38 |
120 |
| 3 |
360 |
230 |
230 |
380 |
1200 |
| 4 |
74 |
50 |
44 |
72 |
240 |
| Total |
780 |
590 |
585 |
805 |
2760 |
The data is the number of progeny in each of the four genetic classes
from the testcross of AaBb x aabb. There are four
testcross families.
- (a) Calculate the Chi-squares for locus A, locus B segregation ratios,
and independence between the two loci. Test for deviation
from the expected overall 1:1:1:1 ratio for each family
seperately. Show that for each cross considered individually,
the three individual 1df chi-squares sum to the 3df
overall chi-square for each of the four families.
(b) Test for heterogeneity for each locus individually. Test for heterogeneity
for independence between loci, and report your overall conclusions.
Provide a significance level for each calculated chi-square test and
the degrees of freedom for heterogeneity.
- Determine the estimated recombination (r) between the A and B loci
for each cross.
Copyright
2000©, Ted Helms
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