The science version of the Adam and Eve Bible story bases the origins of the first man and woman on the planet on DNA analysis. The crazy thing is, that based on this DNA evidence, the genetic ancestor of all men living today lived tens of thousands of years apart from the genetic ancestor of all females. If this is true, their coming together would indeed be a miracle! According to Peter Underhill and other researchers at Stanford University in California, the DNA differences occur because “They had different molecular clocks. Fewer men participated in reproduction than women did.” Underhill’s team, in conjunction with geneticists across the United States, Europe, Israel and Africa, found that the most recent male common ancestor lived in Africa around 59,000 years ago. They based this finding on genetic DNA analysis of the Y chromosomes of over 1,000 men in 22 geographic areas. Y chromosomes, which are only present in men, allow scientists to “count” generations by studying gradual genetic mutations. “The history of our species is something on the order of 4,000 or 5,000 generations,” Underhill said.
To trace the history of women, researchers employ mitochondrial DNA, which passes from mother to daughter almost unchanged. This evidence shows that our ancestral “Eve” lived more than 140,000 years ago. That’s a nearly 80,000 year difference.
Does this mean that the first Eve had to wait around 80,000 years before she met her man? Not exactly. Underhill’s team found that the male genetic legacy was less well-recorded than the female one. How does this occur? Underhill has some ideas. “One tribe conquers another tribe. The dominant tribe, the successful tribe, gets to mate with all the women — its own women plus the women they conquered,” Underhill said. This would lead just the dominant males to pass on their genetic traits, leaving the rest to disappear into history. Chance also plays a role.
“I’m a man and if I get married and just by chance, a flip of the coin, I only have daughters, that is a random chance event. It has nothing to do with my being inferior or superior,” Underhill said.
This would case the man’s Y chromosomes to be wiped from history, and therefore not contribute to the genetic path traced by that method.
Though scientists colloquially refer to these first humans as “Adam” and “Eve,” it doesn’t mean that they were the only male and female alive, nor the only ones to reproduce, according to InspiringScience.Net. In the case of Eve, it just means that “there is an unbroken line of ancestry from every human alive today back to her through the [mitochondrial DNA] mtDNA inherited from their mother, grandmother, great-grandmother, and so on….While the children are descendants of their grandmothers on both sides, their mtDNA lineage can only be traced through their mother to her mother; if only this small group were considered, the maternal grandmother would be “mitochondrial Eve.”
And, “a similar tale can be told of Y-chromosomal Adam; there may have been nothing exceptional about him during his life and living humans are descended both from him and from his male contemporaries, but only the line of descent from him is uninterrupted by a female.”
Read more about the myth and truth behind Adam and Eve here.
Source: CNN, Insiring Science