Mitochondrial Inheritance

Unlike nuclear genes, which are inherited from both parents, mitochondrial genes are inherited only from the mother. In the case of humans,  the mother contributes mitochondria to the zygote, by way of the egg’s cytoplasm. Sperm do contain mitochondria, but they are not usually inherited by the zygote. There has been a reported case of paternal inheritance of mitochondria in a human, but this is extremely rare.

As mitochondria are inherited from a person’s mother, they help to trace matrilineal ancestry.