Question

a gene is composed of two alleles. an allele can be either dominant or recessive. suppose that a couple, who are both carriers of the sickle - cell anemia allele but do not have the disease, decide to have a child. because both parents are carriers of the disease, each has one dominant normal - cell allele (s) and one recessive sickle - cell allele (s). therefore, the genotype of each parent is ss. each parent contributes one allele to their offspring, with each allele being equally likely. complete parts (a) through (c).
(a) genes are always written with the dominant gene first. therefore, there are two instances the offspring could have genotype ss (if one contributes the dominant allele and the other contributes the nondominant allele, and vice versa). list the other two possible genotypes of the offspring.
(use a comma to separate answers as needed.)

Explanation:

Each parent has genotype \( Ss \). When they contribute alleles, possible combinations are:

• If both contribute dominant \( S \): genotype \( SS \).
• If both contribute recessive \( s \): genotype \( ss \).

Answer:

\( SS, ss \)