Question

If the wrinkled-wing mutation in Drosophila is dominant and designated Wr, a fruit fly with the genotype Wr+ Wr+ would exhibit what phenotype?

A) wrinkled wings;
B) wild-type wings;
C) partially wrinkled wings;
D) no wings;
E) one wrinkled wing and one normal wing

Answer 1

A fruit fly with the genotype 'Wr+ Wr+' would exhibit wrinkled wings, as 'Wr' is the dominant allele for the wrinkled-wing mutation in Drosophila.

Step-by-step explanation:

If the wrinkled-wing mutation in Drosophila is dominant and designated by the symbol 'Wr', and we have a fruit fly with the genotype 'Wr+ Wr+', the fruit fly would exhibit wrinkled wings. This is because the '+' sign typically denotes the wild type or normal allele, while 'Wr' represents the mutant allele which causes wrinkled wings. Since it is a dominant trait, the presence of just one 'Wr' allele is enough to display the wrinkled-wing phenotype.

The correct answer to the question is A) wrinkled wings. Dominant traits are expressed phenotypically when at least one dominant allele is present. Therefore, even though the fruit fly has one normal allele (represented as the '+'), the presence of the dominant 'Wr' allele will result in wrinkled wings.