Today I read a short article by Daniel Falk and Francis Collins on Y-chromosome Adam and Mitochondrial Eve (see here). As I understand it we can trace back through the generations of women to the woman from which all women originated. She lives about 150,000 to 200,000 years ago. Likewise, we can trace the Y-chromosome back to the man from which all men originated. It appears he was alive about 50,000 years ago.
This data would suggest that the woman from whom all modern women come and the man from whom all modern men come could not have been a couple. There seems to be a chronological and geographical separation. Does this say anything significant about a literal Adam and a literal Eve?
I have a question that maybe the more scientifically astute can address. Does this data prevent there from being a original human couple from which two strands of humans resulted: one in which we find the modern mother of all women and a different one from which we find the modern father of all men? I find the data confusing. Anyone?
I don’t think this tells us anything about the first humans. Many Christians would argue (such as Hugh Ross and the Reasons to Believe crew) that these dates, rather than disconfirming the Biblical story of Adam and Eve, confirm the Biblical story about the flood. At the flood, there was a genetic bottleneck in the human species. On the male side, only one family’s genetic information was preserved (no diversity), whereas on the female side the genetic information of up to four different women was preserved (genetic diversity). So we would expect for the data to show the last common male human ancestor to be younger than the last common female human because the Y chromosome experienced a greater bottleneck.
I should add that clearly, even on an evolutionary account, male and female are presumed to be the same age. After all, it would be rather difficult for the females to procreate for 150K years without any males! They believe there were human couples going all the way back up to 200K years ago. What they say is that for whatever reason, the genetic information of all males living prior to 50K years ago came to a dead end (some sort of genetic bottleneck, possibly caused by near-extinction of male humans). Only a few closely related, lucky guys who survived managed to pass on their genes to all mankind. For whatever reason, female humans did not experience the same sort of restrictive bottleneck the men did, and thus their DNA goes back further in time.
Jason,
Thanks for commenting. That was one of the problems I was having. I was wondering what this even meant for human life in general. That 150,000 year gap didn’t make a lot of sense to me.
Let me give you a hypothetical situation to explain the difference. Assume by hypothesis that all of humanity was wiped out by a natural disaster, such as a world-wife. Only one man, his mate, his sons and their wives survive. (Perhaps they were on a boat.) For the sake of convenience, let’s call him Noah, and they repopulated the earth.
In this bottleneck scenario, Noah would be most recent common male ancestor through a strictly male lineage (i.e., Noah would be the Y-Chromosome Adam). Mitochrondrial Eve, on the other hand, would not be Noah’s wife, but the most recent common female ancestor of his daughters-in-law through a strictly female lineage. This ancestor must go back much earlier than Noah himself.
Stephen,
Is this a backward proposition for the authenticity of the Noah story? 🙂
No, but that is very helpful and it brings up a lot of interesting thoughts. According to the current predominate theory don’t they separate these two from each other geographically as well? Would that matter?
As I said, it is a hypothetical scenario merely to illustrate how “Eve” can be older than “Adam.” 😉
I’m not familiar with the particular details of the geographical differences, alas, and I have no clue how they can possibly tell, unless it’s going from an estimated age to a corresponding geography based on some notion of the dispersal of the human species over time.
Eve older than Adam?! That is even more confusing!
I think they postulated that one branch can be traced to Africa because some sort of DNA mutation leads the lineage back there. I don’t know enough to speak to that though.
Even with the long lifespans in Genesis, Adam and Eve couldn’t have been that far apart. After all, they had a number of children. Or did Adam just figuratively “know” his wife and have figurative children? 🙂 From those who say it is all figurative, I’d like to know who the first “real” person was in the Bible?
That whole bottleneck thing is interesting.
Blessings,
Derek
It would be impossible to conclude that there was some cataclysm that happened.. say 60,000 years ago in which a single “very lucky” man survived… and say a million women survived, distributed across the African continent, and they all happened to have children from this one very busy man within the 30 or so years of their “fertile lifetime”.
It would be more likely that 60,000 years ago something happened that caused the males of a certain family to be more likely to reproduce than the males of other families. Perhaps they were smarter, better hunters, more widely traveled, more promiscuous, more handsome, or something. So, over time this one male’s genes multiplied while others male’s genes didn’t get passed on. Over a period of time, perhaps thousands of years the other male’s genes eventually died out of the population.
Since we are tracing the “Y” chromosome, and it is random for other chromosomes to be passed on to males or females independent of lineage, it is unlikely this is associated with something like plague resistance which would then only be carried by the men and not the women lacking the “Y”.
I believe that in many polygamous animal species, a higher percentage of females have offspring than males. And, thus they females would likely maintain separate lineages longer. Anything that would selectively favor certain male lineages could eventually lead to the extinguishing of other male lineages.
Or, it could be possible for a “warrior tribe” to spread by conquering other tribes, and taking the females, essentially terminating the male lineages of the conquered tribes while preserving the female lineages.
If we could find DNA samples of prehistoric man, say 50,000 years ago, it would not be unexpected to find mitochondrial DNA from a surviving female bloodline, but also find “Y” chromosomes from male bloodlines that died out, as well as find the “Adam” lineage “Y” chromosomes.
More likely is that when Aliens, who we now look like, came to earth and mated with the female of our species at that time, therefore the male offspring would be the most recent but the original female obviously much older? Is that plausible/possible?