sci-libs/io_lib-1.10.1.ebuild has a block with bioperl (current is 1.6.9). However, one cannot install bioperl with disabled support for the data formats accessible via io_lib.
Basically, I don't care about the extra feature of bioperl but I do want to use recent io_lib. Not sure where to look in the bioperl bundle for that "feature", nor where to tweak the Makefile.PL or whatever. Thank you.