Question

The genotypes for both parents are DD and DD for a genetic trait. Their children all have a genetic disorder. Which genetic disorder do they most likely have?

Answer 1

The children most likely have an autosomal recessive disorder, such as Tay-Sachs disease or cystic fibrosis.

Step-by-step explanation:

The most likely genetic disorder that the children have is an autosomal recessive disorder. In this case, both parents have the genotype DD, which means they have a dominant allele for the trait. However, their children all have the disorder, indicating that they must have inherited two recessive alleles for the trait. Examples of autosomal recessive disorders include Tay-Sachs disease and cystic fibrosis.

Answer 2

The disease hemophilia is caused by a single gene that is located on the X chromosome. Because human females have two X chromosomes (XX), they have two copies of this gene. Since hemophilia is recessive (h), a female must have two copies of the recessive allele to have the disease.