Question

A genetics engineer was attempting to cross a tiger and a cheetah. She predicted a phenotypic outcome of the traits she was observing to be in the following ratio 4 stripes only: 3 spots only: 9 both stripes and spots. When the cross was performed and she counted the individuals she found 50 with stripes only, 41 with spots only and85 with both. According to the Chi-square test, did she get the predicted outcome?

Answer 1

Step-by-step explanation:

this is answer for the question

Answer 2

Given:

Expected phenotypic ratio  => stripes only:  spots only:  both stripes and spots = 4 : 3 : 9

Observation:  50 stripes only, 41 spots only,  and 85 both

To find:

Whether the prediction was right or not

Solution:

Total number of individuals, N = 50+41+85 = 176

The expected ratio, when applied to 176 individuals, gives the following distribution:

4 stripes ⇒ X= 44 individuals

3 spots⇒ X = 33 individuals

9 both ⇒ X = 99 individuals

Applying the Chi-square test,  X² = Σ (Obs-Exp)² / Exp

1. For Stripes only = 0.82
2. For spots only= 1.94
3. For both spots and stripes= 1.98

X² = Σ (Obs-Exp)² / Exp = 0.82 + 1.94 + 1.98 = 4.74

Degrees of freedom = n - 1 = 3 - 1 = 2

Significance level, 5% = 0.05

Table value/Critical value = 5.991

X² < CV

4.74 < 5.99

There is not much deviation between the expected and the observed result. This may be due to mutation.

Hence, she did get the predicted outcome.