|The divine comedy|
Because the Y chromosome in human males is only passed down through males, it is possible to trace lineage from son-to-father backwards in time. Accounting for minor genetic mutations over time, males can find common ancestors (which is how scientists were able to determine that 0.5% of all human males on Earth, and 8% of all Asian men, are descended from prolific lover/rapist/rapist developer Genghis Khan).
Y-chromosomal Adam was a real person, but is named after Adam from Book of Genesis in the Old Testament of the Bible. In Christian mythology, Y-chromosomal Adam would actually be Noah; in reality, scientists don't know who Y-chromosomal Adam actually was (and the odds are good that he wasn't the named Adam or Noah). Unlike Adam from the Bible (and very much like Noah), Y-chromosomal Adam was not the only male on Earth; instead, all of his male contemporaries failed to produce exclusively male lineages that continue to live today.
It is also understood that Y-chromosomal Adam and Mitochondrial Eve, unlike Biblical Adam and Eve, need not have lived together in the same location or period of time, and were almost certainly not mates.
 How long ago did he live?
Calculations by the geneticist Spencer Wells have shown that this man lived around 60,000 years ago. Other calculations put the time of Y-Adam as far back as 142,000 years ago, over twice that of Wells' date.
In 2013, a recently-deceased man was found whose Y-chromosome DNA did not match any of the others previously acquired. This new information would now put the estimate for Y-chromosomal Adam to have been alive 340,000 years ago.. However, this value was derived from a low estimate of the mutation rate. More recent estimates of the mutation rate, based on ancient DNA data, suggest that the date should be ~20% younger.
 See also