Not sure to whom you were addressing your comment - but as a person knowing a bit about statistics ... is a sample of 100,000 valid to draw conclusions for the other 79,900,000 species? Or is that a political poll methodology?
And that whole point was a minor finding of questionable validity in a paper about mitochondrial DNA.
It is possible that a sample size of 100,000 may be enough to draw a proper conclusion. It depends on the sampling criteria and methodology used. That is often why analysts will use a sampling error deviation (e.g. + or - 3%).
The problem with today's political polling methodology (and other polls) is that people deliberately skew the sampling to favor their views never reporting the bias of their own statistics. If a person polls 70% Democrats, then the polls will not be accurate (which is what happens today).