Re: How were scientists able to get a human ear on a mouse?

The experiment in which a human ear was attached to a mouse's back was 
perfomed in the laboratory of Dr. Charles Vacanti at the University of 
Massachusetts.  He was assisted by Dr Linda Griffith-Cima from MIT.  The 
study was done at the suggestion of a plastic surgeon who was interested 
in developing techniques for attaching ears in children who had external 
ear deformities or had lost ears in accidents.  It was designed to serve 
as a model for tissue engineering.

The mouse used for the study had a defective immune system so it was 
unable to reject the human tissue.  The scientists created a ear-like 
scaffold of porous, biodegradable polyester fabric and then distributed 
human cartilage cells throughout this form.  The entire construct was then 
implanted onto the back of the nude mouse. The mouse nourished the ear as 
the cartilage cells grew to replace the fiber.  The mouse remained healthy 
and alive throughout.  While the cartilage grew in the shape of an ear, it 
was not a functional ear since it lacked any connection to the nervous 
system or internal structure of the ear.