Heteroplasmy refers to the existence of multiple variations or mutations within the DNA of an organism's mitochondria. Synonymous terms for heteroplasmy might include mitochondrial polymorphism or mitochondrial heterogeneity. Other possible related terms might include mtDNA diversity, mtDNA heterogeneity, or mtDNA variation. These terms all relate to the concept of variation or diversity within the mitochondrial genome. They can be used to describe the presence of multiple mitochondrial haplotypes within a single individual or within a population, and can be important for understanding the genetic diversity and evolution of different species, as well as for diagnosing and treating mitochondrial diseases.