A variable trait in corn is the presence or absence of knobs at particular sites on some chromosomes.The allele present on each chromosome determines whether or not that chromosome has a knob.Suppose that one member of each of two pairs of homologs in a corn plant has a knob.If this plant is crossed with a knobless plant, what percentage of the offspring is expected to have only knobless chromosomes?
A)100%
B)75%
C)50%
D)25%
E)0%

Question

Quizplus · Accepted Answer

When a plant with one knobbed chromosome in each homologous pair is crossed with a knobless plant, each offspring has a 50% chance of inheriting a knobbed chromosome from the knobbed parent for each pair. Therefore, the probability of inheriting knobless chromosomes from both pairs is 0.5 * 0.5 = 0.25 or 25%.

A Variable Trait in Corn Is the Presence or Absence