The results of a study of a population is presented in the following table. The "-" indicates that the other allele is unknown Which of the conclusions listed below is correct?
A) The ratios of the offspring in the S- X S - matings conform to the expected ratio for a monohybrid cross.
B) The ratios of the offspring in the S - X S - matings are due to some S - parents being homozygotic and some being heterozygotic.
C) If the S- offspring of the S - X S - matings were mated to the S - offspring from the S - X ss matings there would be no ss offspring all would be S -.
D) All of the S - offspring from the S - X S - matings are homozygotic.

Question

The results of a study of a population is presented in the following table. The "-" indicates that the other allele is unknown  Which of the conclusions listed below is correct?
A) The ratios of the offspring in the S- X S - matings conform to the expected ratio for a monohybrid cross. 
B) The ratios of the offspring in the S - X S - matings are due to some S - parents being homozygotic and some being heterozygotic. 
C) If the S- offspring of the S - X S - matings were mated to the S - offspring from the S - X ss matings there would be no ss offspring all would be S -. 
D) All of the S - offspring from the S - X S - matings are homozygotic.

Quizplus · Accepted Answer

The presence of both S - and S + offspring in the S - X S - matings suggests that some S - parents are homozygous (SS) and some are heterozygous (Ss) for the S allele. This would result in a 1:1 ratio of S - to S + offspring, which is observed in the data. Option A is incorrect because there is no information given about expected ratios for a monohybrid cross. Option C is also incorrect because it assumes that the S - offspring from the S - X S - matings are all heterozygous, which is not necessarily true based on the data provided. Option D is also incorrect because there is no evidence to support that all of the S - offspring are homozygous.

The Results of a Study of a Population Is Presented