Mitochondria is present in almost all the eukaryotes and it contains its own DNA as its genetic material which is double-stranded and circular. The gene located on mitochondrial DNA are inherited only by mothers to their offspring.
As the mitochondrial DNA is transported from the female ovum therefore only mother can transfer the mitochondrial DNA to their children however some theories say that even the paternal mitochondrial gene can be transferred to offspring under some specialized condition.
Therefore it is true that genes located on mitochondrial DNA are usually inherited by mothers in their offsprings.
