"Adam," our oldest relative to date, finally has a date of birth, and it's not 5,764 years ago, when the world was created according to the Halacha. According to two Israeli researchers, the first human walked on earth 209,000 years ago – 9,000 years earlier than what scientists previously thought.
The study was conducted by Dr. Eran Elhaik from the University of Sheffield and by Professor Dan Grauer from the University of Houston and the Tel Aviv University. Their findings contradict a previous study that determined that the discovery of the Y chromosome (present only in men, while women have two X chromosome) predated humanity.
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The two concluded that the first "genetic Adam" is now placed in his rightful place in evolutionary history.
The Israeli scientists' study revealed that Adam lived in the same period as his other half, "Eve", the matrilineal ancestor from whom humans are thought to be descended.
Dr. Elhaik and Professor Grauer reported that they used conventional biological models in their research, which was published in the "European Journal of Human Genetics".
The two researchers dated the birth of the first human with the help of genetic data that were already available. To calculate the age of the Y chromosome, they multiplied the average age in which men have their first child with the number of mutations they detected.
They then divided that number by Y chromosome's mutation rate – or how many years in average it takes for a mutation to appear.
Groups of 'Adams' and 'Eves'
The origin of Adam and Eve, and where they lived, are details that are still under dispute by researchers worldwide. In a previous study conducted at the University of Arizona, it was argued that Adam's Y chromosome was in existence before Eve's mitochondrial DNA. According to the same study, the Y chromosome had already existed 338 thousand years ago, long before the creation of mankind.
"Of course, we can manipulate each one of these variables to make a finding look younger or older,’ Dr. Elhaik told the "Daily Mail" British newspaper. "In our paper, we showed the previous study manipulated all these variable to predate the Y chromosome.
"We can say with some certainty that modern humans emerged in Africa a little over 200,000 years ago. It is obvious that modern humans did not interbreed with hominins living over 500,000 years ago. It is also clear that there was no single 'Adam' and 'Eve,' but rather groups of 'Adams' and 'Eves' living side by side and wandering together in our world.
"We have shown that the University of Arizona study lacks any scientific merit. In fact, their hypothesis creates a sort of 'space-time paradox' whereby the most ancient individual belonging to Homo sapiens species has not yet been born, " Dr. Elhaik added.
Back to the Future – it's the same idea
Drawing on a cinematic analogy, Dr. Elhaik continued his explanation: "If we take the numerical results from previous studies seriously we can conclude that the past may be altered by the mother of 'Adam' deciding not to conceive him in the future, thus, bringing a retroactive end to our species.
"Think of the movie Back to the Future, when Marty was worried that his parents would not meet and as a result he wouldn't be born – it's the same idea."
Another previous study, conducted at Stanford University, determined that Adam and Eve lived during the same time in history, but dated their existence to a different, later period. According to the same study, the first human lived 120,000 to 156,000 years ago, while Eve lived 99,000 to 148,000 years ago.