DNA is written with an alphabet of four letters: A, G, T, and C. One copy of a person’s mtDNA is 16,559 letters long. Sometimes a mutation changes one of the mtDNA letters that a mother passes on to her child. These rare and somewhat random changes allow geneticists to identify families. For example, if your grandmother experienced an early mutation in her mtDNA, her children and any daughters’ children would carry the same changed mtDNA. It would differ, in general, from that in the rest of the world’s population.2"<ref>https://www.creationscience.com/onlinebook/FAQ319.html#wp7074454</ref> | DNA is written with an alphabet of four letters: A, G, T, and C. One copy of a person’s mtDNA is 16,559 letters long. Sometimes a mutation changes one of the mtDNA letters that a mother passes on to her child. These rare and somewhat random changes allow geneticists to identify families. For example, if your grandmother experienced an early mutation in her mtDNA, her children and any daughters’ children would carry the same changed mtDNA. It would differ, in general, from that in the rest of the world’s population.2"<ref>https://www.creationscience.com/onlinebook/FAQ319.html#wp7074454</ref> |