Question

We get our mitochondrial DNA only from our mother and not from our father. Why this DNA don’t get mixed with father’s DNA like it happens in nucleus of zygote?

Answer 1

The mitochondria in human sperm are usually destroyed by the egg cell after fertilization. Also, most mitochondria are present at the base of the sperm's tail, which is used for propelling the sperm cells. Sometimes the tail is lost during fertilization. However, some in vitro techniques like injecting a whole sperm into the egg cell might interfere with this.

Answer 2

Answer:

In sexual reproduction, mitochondria are normally inherited exclusively from the mother; the mitochondria in mammalian sperm are usually destroyed by the egg cell after fertilization. The fact that mitochondrial DNA is maternally inherited enables genealogical researchers to trace maternal lineage far back in time.