The mitochondrial DNA sequences of a large extended family were analyzed and compared to a single male in the family. Which of the relatives' mitochondrial DNA should be a match to this person?

His sisters son

Explanation:

Mitochondrial DNA are small circular chromosomes found inside the mitochondria. They are passed exclusively from the mother to children through the egg cell therefore it is maternally inherited.

In the given question. Mitochondrial DNA of an extended family was sequenced and compared to a single male.

His sisters son will match because the person and the sister will have similar mitochondria since they have the same mother. The sister will pass it down to her son.