Y-chromosomal Adam

In human, Y-chromosomal Adam (Y-) is the   (mrca) from whom all s in living men are descended. Y-chromosomal Adam is thus the male counterpart of (the mt-mrca), the  human most recent common ancestor, from whom all  in living humans is descended.

By analyzing DNA from people in all regions of the world, geneticist has concluded that all humans alive today are descended from a single man who lived in  around 60,000 years ago.

Time frame
Y-chromosomal Adam probably lived between 60,000 and 90,000 years ago, judging from and  studies. While their descendants certainly became close intimates, Y-chromosomal Adam and mitochondrial Eve are separated by at least 30,000 years, or possibly a thousand generations. This is due to the differences found in male and female reproductive strategies.

The more recent age of the Y-mrca compared to the mt-mrca corresponds to a larger of the probability distribution for a  man to have living descendants compared to that of a Paleolithic woman. While fertile women had more or less equally distributed chances of giving birth to a certain number of fertile descendants, chances for fertile men varied more widely, with some fathering no children and others fathering many, with multiple women.

Y-chromosomal Adam is not the same individual at all points in human history; the Y-mrca of all humans alive today is different from the one for humans alive at some point in the remote past or future: as male lines die out, a more recent individual becomes the new Y-mrca. In times of rapid population growth, patrilineal lines are less likely to die out than during a.

Naming
Y-chromosomal Adam is named after the of the  as a metaphor only. The name may seem to imply that Y-chromosomal Adam was the only living male of his time; he was not. "Y-Adam" is not even a single fixed individual but a title that continually passes on to more recent individuals as time goes on.