I see. Good points!
There is absolutely nothing in genetic research to even remotely suggest even the most infinitesimal possibility of one-family bottleneck in human genetics within the timeframe that the mythical Noah and Adam would've lived.
Abraham had eight named sons in the Old Testament. Many were never named, but were implied, by his concubines. He, being the Father of all Jews, Levites, Benjaminites, Arabs, Edomites, Midianites, and the Lost tribes of Israel, his genetic material, ie DNA, must be spread all over the planet......
Timeframe issues aside (which are huge, admittedly), there were plenty of 1-heatbeat genetic bottlenecks.
Google:
"Y-chromosome Adam"
"mitochondrial Eve"
Basically, all humans share at least one, and probably more than one, male and femal ancestor.
Of course, they can't say --- with any certainty --- that the given, proven "adam" (a real misnomer) and "eve" (same) lived at remotely the same time.
That said, obviously each of the bottlenecks had parents, who could presumably qualify.
And yes, I am greatly over-simplifying for brevity.
And no, I am not saying that this is proof of Genesis.
Just that the science and the Bible are not inconsistent, which is something both sides of such debates often forget.
That is why it is called "faith".