For humans, it was the greatest catastrophe. Remember Permian-Triassic period didn't just affected one species and there were no humans during that period. You could say our ancestors were affected though.
There is the Toba catastrophe theory - basically that the huge eruption of Toba caused a reduction of the number of breeding pairs of humans down to a few thousand:
Perhaps the volcano wasn't the cause, but IIRC there's reason to think that humans display less genetic diversity than might be expected, pointing towards a bottleneck somewhere in the past.
Humans are very unusual from a genetic perspective that makes analysis of us difficult. Firstly, the population has expand hugely in a very short time so there are all sorts of founder effects. Secondly, the selection presure completely changed a few thousand years ago with the transition from hunter-gather to farming. These two factors make it really hard to use the normal genetic tools and concepts to study human evolution and draw accurate conclusions.
