Question

If the ratio to this expression represents people, which scenario would be illogical?

a) 3:2

b) 1:0

c) 5:1

d) 2:3

Answer 1

The illogical scenario when the ratio represents people is 1:0. In genetics, the expected genotypic ratio for offspring from parents heterozygous for a recessive lethal allele would be 1:2:0, as the homozygous recessive offspring do not survive in utero.

Step-by-step explanation:

If the ratio in the expression represents people, the scenario that would be illogical is b) 1:0. This ratio implies that for every person, there are zero people, which doesn’t make sense in a real-world context. When considering genetic ratios, this becomes particularly important because it relates to expected offspring. For example, in a mating between two individuals that are heterozygous for a recessive lethal allele that is expressed in utero, the genotypic ratio of homozygous dominant:heterozygous:homozygous recessive would typically be 1:2:1. However, since homozygous recessive individuals would not survive in utero due to the lethal allele, the genotypic ratio observed in the offspring would actually be 1:2:0.