Heteroplasmy
![There is a wide variety of mitochondrial DNA genotypes in the maternal pool, which is represented by the bottle. The two genotypes in this maternal pool are represented by blue and yellow. When generated, each oocyte receives a small subsampling of mitochondrial DNA molecules in differing proportions. This is represented by the conveyor belt with oocytes, each one unique, as they are produced.[5]](/Images/godic/202501/18/Mitochondrial_Bottleneck1129.png")
![Sequence illustrating heteroplasmy genotype of 16169 C/T in Nicholas II of Russia.[13]](/Images/godic/202501/18/Heteroplasmy_present_in_Tsar_Nicholas_II1129.jpg")
Heteroplasmy is the presence of more than one type of organellar genome (mitochondrial DNA or plastid DNA) within a cell or individual. It is an important factor in considering the severity of mitochondrial diseases. Because most eukaryotic cells contain many hundreds of mitochondria with hundreds of copies of mitochondrial DNA, it is common for mutations to affect only some mitochondria, leaving most unaffected.