Length variation in HV2 of the human mitochondrial DNA control region

Hair samples were typed from three individuals who exhibited length heterop lasmy in the homopolymeric cytosine stretches (C-stretch) in hypervariable region 2 (HV2). The study demonstrated that for different hairs within an i ndividual, the HV2 C-stretch region can vary with respect to the number of cytosines and/or proportion of C-stretch length variants. Length heteroplas my may occur regardless of the prominent length variant present in this reg ion. Differences in the number of cytosines at the C-stretch region, or a v ariation in the relative amounts of heteroplasmic length variants, cannot b e used to support an interpretation of exclusion.