Genotype and phenotypes (plant breeder and fruit flies)

21. A plant breeder was trying to produce a true-breeding variety of radishes with an oval shape. However, each time plants with oval radishes were self-pollinated, only half of the offspring were oval. The rest of the plants produced were either round or long radishes.

What would be the expected phenotype ratio if plants with round radishes were crossed with plants with oval radishes.

a)   1 round : 1 long
b)   1 round : 1 oval
c)   All oval
d)   All round


36. A Recessive allele causes fruit flies to have white eyes instead of wild-type eyes. This eye color gene is known to be X-LINKED. In a cross between homozygous wild-type females and white-eyed males, all F1 progeny have wild-type eyes.

What ratio of wild-type to white-eyed progeny can be expected in each sex if F1 females are crossed to males of the same genotype as their father?

a)   Males – 0:1 ; females – 1:1
b)   Males – 1:1 ; females – 1:1
c)   Males – 1:0 ; females – 1:0
d)   Males – 1:1 ; females – 1:0