Question

Daphne (female) and Erik (male) are cousins. They both have the same mutation in their mitochondrial DNA. Which of the following statements is most likely to be true?

• A. Both Daphne and Eric will pass the mutation to their children.

• B. Daphne's mother and Erik's mother are sisters.

• C. Daphne and Erik's grandfather also has the mutation.

• D. All of Daphne and Erik's other cousins also have the mutation.

• E. Daphne's father and Erik's father are brothers.

Answer 1

mother passes their mitochondria to their progeny, so sisters who have the same mother have the same mitochondria, which they inherited from their mother and progenies of the sisters also will have the same mitochondrial DNA.

Daphne (female) and Erik (male) are cousins. They both have the same mutation in their mitochondrial DNA.

so the mothers of Eric and Daphne are sisters, and they inherited the mitochondrial mutation from their mother, so maternal grandmother of both Eric and Daphne are the same.

Daphne will pass this mutation to her progeny but Eric will not pass this mutation to progeny.

Cousins who are progenies of their maternal uncles have mitochondria from the mother so they will have different mitochondrial DNA.

B. Daphne's mother and Erik's mother are sisters.

• E. Daphne's father and Erik's father are brothers.