Reasons to Believe

Happy Mother's...DNA?

 “All women become like their mothers. That is their tragedy. No man does. That’s his.”
                       —Oscar Wilde, The Importance of Being Earnest, Act 1
 
Mother’s Day is just around the corner—time to bust out cards, flowers, and breakfast-in-bed to let those special women know just how much they mean to us. We value their love, wisdom, and long-suffering patience. We’re also thankful if we inherited Mom’s eyes or smile. But that’s not all we have to thank Mom for.
 
It may not look good on a Hallmark card, but we should also be thankful for Mom’s mitochondrial DNA.
 
 
The DNA inherited from our mothers holds information valuable in the study of humanity’s origin. In Who Was Adam? Dr. Fazale Rana explains that mitochondrial DNA (mtDNA), circular pieces of DNA found in organelles known as mitochondria, “is nearly ideal for the study of human origins because of its relatively simple pattern of inheritance and its rapid mutation rate.”
 
We each inherit our share of mtDNA exclusively from our mothers’ egg cell. Mitochondrial DNA provides a sort of molecular clock that scientists can use to trace humanity’s history through the maternal lineage. Since the 1980s, multiple experiments by separate research teams have attempted just that. So far the experiments have produced a similar conclusion. Humanity originated in a single location (apparently Africa) from a single woman some several tens of thousands of years ago (estimates range from 100,000 to 200,000). Scientists nicknamed the woman “mitochondrial Eve.” (See details on some of the experiments in Who Was Adam?)
 
Critics of this approach to human origins research point out that molecular clocks based on mtDNA do not necessarily produce highly accurate origins dates. For this reason, as Fuz explains, “the dates for humanity’s origin extracted from genetic data of human population groups must be regarded as ballpark estimates, not ironclad conclusions.” In other words, these dates may not be exact, but they provide a good starting point.
 
Out of Africa
 
The data from the mtDNA studies supports a human origins hypothesis known as the Out-of-Africa Hypothesis. According to evolutionary scientists, this hypothesis suggests humans evolved exclusively from the African hominid Homo sapiens and then migrated around the world.
 
Reasons To Believe (RTB) takes a biblical view of this origins scenario. Here’s a summary of RTB’s human origins creation model predictions as laid out in Who Was Adam?
 
  1. Humanity traces back to one woman (Eve) and one man (Adam, but in genetic terms, Noah).
  2. Humanity’s early population size was relatively small.
  3. Humanity originated in a single location in or near the Middle East.
  4. Humanity’s origin dates back to between 10,000 and 100,000 years ago.
  5. The origin of the female lineage (Eve) predates the origin of the male lineage (Noah because all male survivors of the Flood trace their DNA to him).
  6. God created humanity at the “just-right” time in Earth’s history.
  7. Culture appears and expands explosively in the archeological record since humanity’s origin.
  8. Humans share anatomical, physical, biochemical, and genetic similarities with the extinct hominids [a.k.a. “cave men”] as well as with great apes and other animals.
  9. Humans are behaviorally distinct (in way that reflect God’s image) from earlier hominids, great apes, and other animals.
  10. A universal but regional flood impacted all of humanity and shaped human history.
  11. Human life spans (once longer than 900 years) became progressively shorter after the Flood.
  12. Humanity spread around the world from in or near the Middle East relatively recently.
  13. Human civilization and agriculture emerged in or near the Middle East.
 
The Out-of-Africa Hypothesis helps provide scientific support for RTB’s biblical model. In particular, the hypothesis provides support for a historical Adam and Eve, a fact that is paramount to the inerrancy of Scripture and to the doctrine of Atonement.
 
Another popular origins hypothesis, known as the Multiregional Hypothesis, argues that humanity emerged at roughly the same time, but in different locales and from different groups of hominids. Meanwhile, some scientists hold to what Fuz calls a “Mostly Out-of-Africa Hypothesis,” which suggests that modern humans originated in Africa by interbreeding with hominids in the area. (GROSS!)
 
Fortunately, thanks to Mom’s mitochondrial DNA, evidence favors the Out-of-Africa Hypothesis and, thus, a biblical view of human beings as created in God’s image.
 
So despite Oscar Wilde’s witty comments, what we inherit from our mothers is a blessing, not a tragedy.
 
Happy Mother’s Day to all the moms out there!
 
—Maureen
 
 
Resources:
 
So you might be thinking what does Noah have to do with human origins? If you’d like all the nitty, gritty details on this and other human origins issues, pick up Who Was Adam? at the RTB Web store.
 
Listen to Fuz’s take on arguments that favor human-hominid interbreeding in the May 3 episode of the Science News Flash podcast.

Subjects: Human Origins and the Bible