Assuming basic Mendelian inheritance which of the following

Assuming basic Mendelian inheritance, which of the following are the expected wing phenotype ratios for the F2?

You are a scientist trying to understand how wing shape is inherited in fruit flies. You have flies that are pure-breeding for the wild-type wing shape & flies pure-breeding for a mutant wing shape (zigzag wings). You breed these flies and notice that the F1 are 100% wing mutants. Using your F1 data you\'ve constructed a null & alternative hypothesis. Now you want to attempt to falsify the null hypothesis so you cross a male & female from your F1 generation flies. Assuming basic Mendelian inheritance, which of the following are the expected wing phenotype ratios for the F2? 50% wild-type, 50% wing mutant O 25% wild-type, 75% wing mutant O 100% wing mutant 75% wild-type, 25% wing mutant 100% wild-type

Solution

This case represents to be a general case when the Mendelian pattern of inheritance is being followed and a monohybrid cross is performed in the F1 generation. Thus, the information suggests that the flies in the F1 generation all bear a common genotype i.e. mutant, say Aa in nature. These flies are selfed and the F2 is obtained. Thus, this selfing would obtain following cross:

Genotype: AA: Aa: aa : 1:2:1

Phenotpye: Parental (AA and aa): mutant (Aa):: 1:1

This suggests that choice 1 is the correct answer.

	A	a
A	AA	Aa
a	Aa	aa