[Mrs. Don-o]

You wrote: "Of course tissue rejection, and a number of other issues in applied biology, such as growing human parts replacements on pigs, or anticipating cross-grafts that will bear fruit, has quite a bit to do with mutational distances between the entities in question."

You are making the assumption that relationship = evolutionary relationship. You can certainly compare the tissues, the organs, the antigens, and the DNA of one species and another, and make all the observations necessary to predict the success or the rejection of a graft. This may be, but is not necessarily related to the two species having diverged from a common ancestor two, or five, or ten million years ago.

In other words, the distances between the entities in question, doesn't have to be explained by reference to remote origins. It can be observed directly. That's apparently what this incompetent surgeon, Bailey, did not do.

[donh]

In other words, the distances between the entities in question, doesn't have to be explained by reference to remote origins.

no, it doesn't. It could be explained by tree sprites, or wikkan spells. However, what science likes to deal in is tidy stories that seem to have great predictive consistency and potency, and are fairly economic to arrange tests for that could easily yield negative results if the theory were, in fact, invalid & explain otherwise puzzling things such as, for example, why all living entities can pretty much all eat each other, given, at most, a few intermediate consumers.

It can be observed directly.

Observing things indirectly is a prefectly legitimate, common, and necessary way to do science.