Just to quickly unpack why the prediction of the Human Chromosome 2 fusion is so important.
All great apes have 24 chromosome pairs, except for humans, which have 23 chromosome pairs. This is a problem for common ancestry. If we are close relatives of other great apes, then we should have the same number of chromosomes as them. That’s just plain problematic. In fact, it’s problematic enough that it poses a real challenge to common descent, one that strikes at the heart of the neodarwinian synthesis. The close relationship between humans and chimpanzees was predicted on the basis of fossils and morphology and biogeography and many other lines of evidence. If that turns out to be wrong, it means that there is a fundamental problem with our view of descent and ancestry.
The only solution is a chromosome fusion event. That’s the only way that humans and chimps can share a recent common ancestor: the ancestor must have had 24 pairs, and somewhere along the human line of descent, there must have been a fusion that became fixed in the population. It’s a really specific prediction. One of the human chromosomes must match two chimpanzee chromosomes exactly, with a fusion marker in the middle. That’s the only way. If there are not two adjacent chimpanzee chromosomes pairs that match one human chromosome pair with a fusion marker, common ancestry is toast. Everything falls apart.
Now, the Special Creationists don’t have this problem. If God made humans from scratch, he simply could have made them with a different number of chromosomes. There’s no reason for any of the chromosomes to match those of other great apes. Of course there COULD be a fusion event; God could have originally created humans with 24 pairs that fused into 23. But also maybe there isn’t.
Then, after this prediction was made, we discovered it in 1991. Human chromosome 2 is extra-long. It has the telltale markers of fusion, with two centromeres and embedded telomeres. Its two sides, on either ends of the embedded telomeres, match two chimpanzee chromosomes exactly. You can see it for yourself:
This didn’t falsify special creation, because you can’t falsify special creation, not in this way. God simply could have created them in any way he wanted. But what it did do is prove that the predictions of common descent hold up. Time and time again, common descent makes specific, defined, testable predictions that could falsify it, and time and time again it is proven reliable.