Ancestor by Scott Sigler. Sigler is a sci-fi horror writer but he doesn't write any supernatural elements in his stories. Everything is based in hard science. Ancestor was one of his earlier books, which he originally did as a podcast for free.

It is about the process of xenotransplantation-using animal organs to replace human ones. Whoever solves this will not only help millions of people live longer but will of course become exceedingly rich.

So a group of scientists backed by the requisite mercenary minded corporation with a hidden agenda are working on this issue. As most mammals are far too different from humans to be good organ donors the scientists decide to attempt to recreate the first mammalian ancestor under the idea that its organs will be a match for all of its descendants. Of course things go drastically wrong and bloody events take place.

This should have been a better book. It was one of Sigler's earliest ones and the characters are sort of flat. Insert feuding lovers here, insert cold military man there and so on. The book's tone was very staccato and it was quite apparent that it was written for the radio/internet downloads. It was still fun, just not great. As he does in many (all??)of his books, Sigler uses his home state of Michigan as a setting, specifically the beautiful remote shores and islands of Lake Superior.

In the novel Sigler can't resist taking a few shots at the people who said his business model wouldn't work and also gets in a few digs at Twilight fans.