Medical Genetics 3. Mitochondrial inheritance In mammals. 99. 99%o of mitochondrial dNa (mtDNA)is inherited from the mother this is because the sperm carries its mitochondria around a portion of its tail and has only about 100 mitochondria compared to 100,000 in the oocyteMedical Genetics 3. Mitochondrial Inheritance In mammals, 99.99% of mitochondrial DNA (mtDNA) is inherited from the mother. This is because the sperm carries its mitochondria around a portion of its tail and has only about 100 mitochondria compared to 100,000 in the oocyte