Egan's stuff is hit or miss for me. I'd call this a grazing hit. The book opens with our viewpoint character of Prabir on a tiny island in Indonesia where his parents are studying some very odd butterflies. As Indonesia breaks up, events sweep over them leaving Prabir and his little sister in Canada.
Years later, an expedition is going back to that region to study a large number of mutant animals...
This could have been better. Prabir felt a bit, well, flat, to me. Still, there is an interesting mcguffin behind the mutations - a gene that copies successfull traits from other universes. The problem is, there is a lot behind this that seems left out. Like where did this multi-world spanning gene come from?
Anyway, not time badly spent, but it could have been better.
Science fiction, heavy on the "science" - a strange story of evolution and intrigue, blood ties and biology... Not quite my cup of tea, but well written and worth a look if you're into Sci Fi with a scientific bent.