Pink-eye and albinism are two recessive traits found in the deer mouse, Peromysc
ID: 198889 • Letter: P
Question
Pink-eye and albinism are two recessive traits found in the deer mouse, Peromyscus maniculatus. In mice with pink-eye, the eye is devoid of color and appears pink from the blood vessels within it. Albino mice are completely lacking color both in their fur and in their eyes. F. H. Clark crossed pink-eyed mice with albino mice; the resulting F1 had normal coloration in their fur and eyes. He then crossed these F1 mice with mice that were pink-eyed and albino and obtained the mice shown in the table below. It is very hard to distinguish between mice that are albino and mice that are both pink-eyed and albino, so he combined these two phenotypic classes (F. H. Clark, 1936, Journal of Heredity 27:259–260). Match the expected numbers of progeny with each phenotype if the genes for pink-eye and albinism assort independently.
Use a chi-square test to determine if the observed numbers of progeny fit the number expected with independent assortment.
Please just give me the answer to the calculation of the chi square. Thats all.
Phenotype Observed Expected wild type, wild type 12 38 wild type, pink eyes 62 38 albino, wild type or pink eyes 78 76 Total 152 152Explanation / Answer
So the chi-square value is 33.
There are four alleles involved in the cross os degree of freedom will be 4-1 = 3
Degree of freedom df = number of alleles- 1
For 3 degree of freedom chi-square value for p-0.05 is 7.82.
observed chi-square value is very high than the expected value
No, observed numbers of progeny don't fit the number expected of the independent assortment.
Observed Expected O-E (O-E)2 (O-E)2/E wild-type, wild-type 12 38 -26 676 17.78947 wild-type, pink eyes 62 38 24 576 15.15789 albino, wild-type or pink eyes 78 76 2 4 0.052632 Total 152 152 33