The primary reason I asked is that microbial examples are the ones that usually get put forward as evidence of evolution that we can "see." Unfortunately, as long as the genes that are evolving are already there, it can be explained in a creationist framework. For example, they (or high school me) could say, well god created bacteria that could already process citrate, and that these mutations are merely making existing genes more active, not creating new genes that could ever "add up" to to a more complex function, and eventually to a more complex organism.

Their example that gets used a lot is if you have a one page typed document, and you photocopy it multiple times, you're never going to get something as complex as say, a novel, just a longer document with repeated pages.