That's not exactly how an evolutionist would word it, Boulder, but fair enough.

The most recent common ancestor (of all humans) is estimated to be about 60,000 years old and is called "Y-Chromosomal Adam". I don't know what you heard, Clint - but I'm not going to shoot it down. I'm skeptical because there are still lots of "pure" tribals in South America and Africa, which couldn't have feasibly intermingled within the last 45,000 years or so. If that number had to do with ethnic or regional or continental groups, though, I wouldn't be surprised.

It is sort of an umbrella effect, after all, he's not required to mate with every female in existence at the time, one of his male offspring is.

The tricky population wouldn't even be South America, it was only populated 12k-15kyears ago, compared to North American migrations 25k-35k and 7k-9k years ago. The real trick would be the first wave of Indian sub-continent migration which pushed over to the Australian migration, over 60k years ago.

People. We sure do move around a lot!