Xena, Clone Princess

[Rcjohnsen]

Xena, Clone Princess

Amid the rush to clone various types of mammals in the wake of 
the celebrated 1997 unveiling of Dolly the sheep, the cloning of 
pigs has represented a particular opportunity -- and challenge.  
Because of their close physiological ties with humans, cloned pigs 
could constitute an excellent source of organs for transplantation.  
But the details of porcine reproductive biology have made 
successful cloning of pigs a thorny proposition.  The 18.8.2000 
issue of Science offered the first full scientific report of pig 
cloning, in a study by Onishi et al. 
(http://www.sciencemag.org/cgi/content/short/289/5482/1188).  As 
a related news story 
(http://www.sciencemag.org/cgi/content/summary/289/5482/1118) 
explains, the researchers accomplished the feat by microinjecting 
skin fibroblast nuclei from a black breed of pig into enucleated egg 
cells, stimulating development with electrical pulses, and 
transferring the growing cells into surrogate mothers.  The result 
was Xena -- a black piglet, born to a white sow.  A Perspective by 
R. S. Prather in the 15.9.2000 issue 
(http://www.sciencemag.org/cgi/content/summary/289/5486/1886) 
discussed this and other cloning efforts, and new concerns that 
have been raised about the safety of pig-to-human 
xenotransplantation.