Causing genetic bottleneck?
Some effect, no doubt.
Professor Bryan Sykes says that the Europeans were driven back to the Ice Age Refuges during the Younger Dryas. Professor Stephan Oppenheimer says that some European populations outside the refuges weathered the YD in place...so, there's some disagreement among experts.
Now, some genetists say that the Sa'ami's (Laplanders) left the refuges early at the end of the Ice Age and were isolated from the larger European population for a long time...I wonder if that isolation wasn't during the YD. The Sa'ami are so unique that they are described as having a Sa'ami Motif.
"It is curious, however, that the mitochondrial DNA of the Samis should differ so distinctly from that of other European peoples. The "Sami motif" which has been identified by researchers - a combination of three specific genetic mutations - is shared by more than one third of all tested Samis, but of all the gene tests conducted throughout the world, the same mutation has occurred in only six other samples, one Finnish and five Karelian."
That seems like one of the biggest problems with this theory. The genetic evidence does not show all of North America being repopulated from a small group of survivors of a catrastrophic event.