What is true about mutations in mitochondrial DNA?

Mitochondrial DNA is unique because it is primarily inherited maternally. This means that when an egg is fertilized by a sperm, the mitochondria in the sperm are typically discarded during the formation of the zygote, leaving only the mitochondria from the egg to be passed on to the next generation. As a result, any mutations that occur in the mitochondrial DNA can be passed down from the mother to all of her offspring, regardless of their sex. This maternal inheritance pattern is significant in studies of genetics and evolution because it allows researchers to trace lineage and understand the transmission of certain genetic conditions.

In contrast, paternal contributions to mitochondrial DNA are usually not transmitted to offspring, which makes the maternal inheritance a defining characteristic of mitochondrial genetics. This aspect plays a crucial role in understanding various mitochondrial diseases and disorders, reinforcing the notion that mitochondrial mutations predominantly come from the maternal side.