Question

tay - sachs disease is caused by a mutation in the hexa gene located on chromosome 15. tay - sachs follows an autosomal recessive pattern of inheritance. with the help of the diagram, identify which of the offspring will be an unaffected carrier

Explanation:

Autosomal recessive inheritance means:

1. Fully blue (A) = affected (homozygous recessive, has the disease)
2. Half blue/half white (B, C) = unaffected carrier (heterozygous, has one defective allele but no symptoms)
3. Fully white (D) = non-carrier, unaffected (homozygous dominant, no defective alleles)

Unaffected carriers have one normal and one mutated allele, so they show no symptoms but can pass the mutation to offspring.

Answer:

B. Half-blue/half-white male, C. Half-blue/half-white male