What are the average number of differences between two full length mtDNA sequences?
The average number of polymorphisms that differ between two human mitochondrial genomes is 38.5 among non-Africans, 76.6 among Africans and 61.6 among all humans (Ingman et al. 2000). The number of differences in the mitochondrial DNA of any two people depends on how long ago they shared a common maternal ancestor. Members of haplogroup H – which split into several sub-haplogroups fairly recently, perhaps 8000 years ago – have on average seven to eight differences (Coble 2004). People of African descent have more polymorphic differences, about 77 on average, because they represent the oldest branches of the mtDNA tree.
