1. In fruitflies, scarlet eyes (s) is autosomallyrecessive to wild-type color; ebony body is autosomally recessiveto wild-type body. The traits are located on the 3rdchromosome & are 26 cM apart. A wild-type female istest-crossed (see cross below). Based upon the information given,complete the chart.
P: s + X s e
+ e s e
Genotype Phenotype Expected%
Total: 100%
PHENOTYPE
EXPECTED FREQUENCY
OBSERVED FREQUENCY
(O â E)
(O â E)2
(O â E)2/E
Wild-type for both traits
90
scarlet & ebony
85
Scarlet & wild-type body
275
Wild-type eyes & ebony
300
Total
750 total flies
750 total flies
X2 =
x^2= e(O-E)^2/E
Degrees of freedom (n) 5% Probability Value (P) 1 3.84 2 5.99 3 7.81 4 9.49
What are your degrees of freedom for thisquestion?___________ (n = phenotypes -1 )
Does the data fit the hypothesis/expected (have aX2 value < 5% P value for that n)?
_______________
1. In fruitflies, scarlet eyes (s) is autosomallyrecessive to wild-type color; ebony body is autosomally recessiveto wild-type body. The traits are located on the 3rdchromosome & are 26 cM apart. A wild-type female istest-crossed (see cross below). Based upon the information given,complete the chart.
P: s + X s e
+ e s e
Genotype Phenotype Expected%
Total: 100% |
PHENOTYPE | EXPECTED FREQUENCY | OBSERVED FREQUENCY | (O â E) | (O â E)2 | (O â E)2/E |
Wild-type for both traits | 90 | ||||
scarlet & ebony | 85 | ||||
Scarlet & wild-type body | 275 | ||||
Wild-type eyes & ebony | 300 | ||||
Total | 750 total flies | 750 total flies | X2 = |
x^2= e(O-E)^2/E
| Degrees of freedom (n) | 5% Probability Value (P) |
| 1 | 3.84 |
| 2 | 5.99 |
| 3 | 7.81 |
| 4 | 9.49 |
What are your degrees of freedom for thisquestion?___________ (n = phenotypes -1 )
Does the data fit the hypothesis/expected (have aX2 value < 5% P value for that n)?
_______________
