Question

Suppose we have a disease phenotype that is determined by a single gene with two alleles. Further suppose it follows a autosomal recessive mode of inheritance with reduced penetrance. We have an individual who is unaffected (does not have the disease phenotype) and whose genotype is unknown. We cross this individual with a true-breeding affected individual. How many possible genotypes can this unaffected individual have at the disease locus

Answer 1

three (3)

Step-by-step explanation:

Penetrance can be defined as the proportion of individuals that have mutations associated with a genetic disorder and exhibit symptoms of having that genetic disorder. Moreover, reduced penetrance, also known as incomplete penetrance, indicates that an individual who carries mutations for a disorder but may never develop this disorder. Incomplete penetrance is frequent in some types of cancer, where individuals carry mutations (for example, mutations in the BRCA1 gene which is associated with an increased risk of ovarian cancer), but they may do not develop this condition during their lifetime. Incomplete penetrance may be a result of the interaction between genetic and environmental factors.