Joined: Oct. 2009
Just refer them to the Evolution on a Chip article. The end result was a 90-fold increase in efficiency and there were 4 mutations (some of which were multiple nucleotides) that resulted in this.
So, not only can it happen, it DOES happen and in a controlled environment in which no designer was found fiddling with the RNA sequence.
You can also refer them to the Kitzmiller vs. Dover ISD court transcript in which Michael Behe is toasted on the same subject.
In short, let's say that there is a 1 in trillion trillion chance for the mutations to occur. Unfortunately, the creationists forget that there is a trillion bacteria in a few grams of soil (for example) and there are many trillions of grams of soil in the world.
So, even a trillion trillion chance approaches 1 when one is discussing all life on the planet.
Sure, it's more difficult to deal with something like this in large animals and plants, but then (as the creationists remind us) large animal and plant populations change very slowly.
I would encourage you to read the Kitzmiller trial testimony (at least the experts), it's a textbook list of modern creationist arguments.
Ignored by those who can't provide evidence for their claims.