TOKYO, Aug 8, 2007 (AFP) - Japanese researchers said Wednesday they had created a fourth-generation cloned pig in a world-first achievement that could lead to new transplant treatments for humans.

It is the first time that scientists have cloned such a large animal over successive generations, said Hiroshi Nagashima, a bioscientist leading the project at Meiji University.

He said the male pig -- whose forebearers starting from his great-grandfather were also cloned in laboratories -- was born on July 23 at the university in Tokyo.