Cornelius and Janelle sought genetic counselling because of concern that they might have children with sickle-cell anemia.The counsellor determined they each have one recessive allele for sickle-cells and one dominant allele for healthy blood cells.The counsellor would tell them that they have a

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Cornelius and Janelle each have one recessive allele for sickle-cells and one dominant allele for healthy blood cells. This means that both parents have a 50% chance of passing on the sickle-cell allele to their child. If both parents pass on the sickle-cell allele, the child will have sickle-cell anemia. Therefore, there is a 25% chance (0.5 x 0.5) that they will have a child with sickle-cell anemia and a 50% chance (0.5 x 0.5 and 0.5 x 0.5) that they will have a child with sickle-cell trait.

Cornelius and Janelle Sought Genetic Counselling Because of Concern That