While doing a pedigree analysis of a European royal family, you notice a disease in a female child of two healthy parents. There are also some cousins with the same genetic disease. If this disease is controlled by a single gene, then the MOST likely explanation for these observations is that the disease is:
A)a spontaneous mutation.
B)recessive and only seen in homozygous recessive individuals such as the daughter.
C)dominant and only seen in homozygous dominant individuals such as the daughter.
D)only seen in heterozygous individuals such as the daughter.
E)dominant and is seen in homozygous dominant or heterozygous individuals.

Question

Quizplus · Accepted Answer

The presence of the disease in a female child of two healthy parents suggests that the parents are heterozygous carriers for the recessive gene. The occurrence of the disease in cousins further supports the possibility of the gene being recessive. Therefore, the disease is most likely recessive and only seen in homozygous recessive individuals such as the daughter.

While Doing a Pedigree Analysis of a European Royal Family