“However, there is a way to know for certain that Noah’s Flood and the Creation story never happened: by looking at our mitochondrial DNA (mtDNA). Mitochondria are the “cellular power plants” found in all of our cells and they have their own DNA which is separate from that found in the nucleus of the cell. In humans, and most other species that mitochondria are found in, the father’s mtDNA normally does not contribute to the child’s mtDNA; the child normally inherits its mtDNA exclusively from its mother. This means that if no one’s genes have mutated, then we all have the same mtDNA as our brothers and sisters and the same mtDNA as the children of our mother’s sisters, etc. This pattern of inheritance makes it possible to rule out “population bottlenecks” in our species’ history. A bottleneck is basically a time when the population of a species dwindled to low numbers. For humans, this means that every person born after a bottleneck can only have the mtDNA or a mutation of the mtDNA of the women who survived the bottleneck. This doesn’t mean that mtDNA can tell us when a bottleneck happened, but it can tell us when one didn’t happen because we know that mtDNA has a rate of approximately one mutation every 3,500 years (Gibbons 1998; Soares et al 2009). So if the human race were actually less than 6,000 years old and/or “everything on earth that breathed died” (Genesis 7:22) less than 6,000 years ago, which would be the case if the story of Adam and the story of Noah’s flood were true respectively, then every person should have the exact same mtDNA except for one or two mutations. This, however, is not the case as human mtDNA is much more diverse (Endicott et al 2009), so we can know for a fact that the story of Adam and Eve and the story of Noah are fictional. There”
―
Alexander Drake,
The Invention of Christianity