Homoplasmy

Homoplasmy is a term used in genetics to describe a eukaryotic cell whose copies of mitochondrial DNA are all identical.

Unlike almost all animals, this species has biparental inheritance for mitochondrial DNA, meaning that both the male and the female contribute mitochondria to the offspring.

This means that fusion can be used to generate complementary nucleoids if a mutation causes one mitochondria to no longer be functional.

[10] Leber's hereditary optic neuropathy (LHON) is the disease in humans that is most frequently associated with homoplasmy.

[11] Although it is passed down maternally, it is seen more often in young men than in other ages or sexes, which leads researchers to believe that there are many other genetic or environmental factors that contribute to developing the disease.

[11] Specifically, researchers have thought that the genetic component outside of the mitochondria would be on the X chromosome; however, in multiple studies, there have been no findings that suggest this.

Some research has shown that an inherited heteroplasmic mutation can cause cancer in older age as cells become homoplasmic.

The cell in the top left is heteroplasmic as shown by the normal mitochondria in purple and the mitochondria with a mtDNA mutation in red. As this cell divides, the mitochondria replicate and independently assort into the daughter cells. This leads to both positive and negative (cell shown in red) homoplasmy.