abstract = "Adding new functionality to an existing, large, and
perhaps poorly-understood system is a challenge, even
for the most competent human programmer. We introduce a
grow and graft approach to Genetic Improvement (GI)
that transplants new functionality into an existing
system. We report on the trade offs between varying
degrees of human guidance to the GI transplantation
process. Using our approach, we successfully grew and
transplanted a new Babel Fish linguistic translation
feature into the Pidgin instant messaging system,
creating a genetically improved system we call Babel
Pidgin. This is the first time that SBSE has been used
to evolve and transplant entirely novel functionality
into an existing system. Our results indicate that our
grow and graft approach requires surprisingly little
human guidance.",