A hair recovered from the ligatures binding one of the murdered children was subjected to mitochondrial DNA analysis and found to be consistent with Terry Hobbs, the stepfather of one victim. Investigators and defense attorneys presented this as significant evidence pointing toward Hobbs. However, mitochondrial DNA has a specific limitation that means this finding cannot exclusively identify Hobbs as the source of the hair. What is that limitation, and what category of individuals would share identical mitochondrial DNA profiles with Hobbs?