World's First Cloned Mouse Dies
3:40 AM EDT; May 10, 2000; Honolulu, HI (AP) -- Cumulina, the world's first cloned mouse, has died of old age. The University of Hawaii Medical School said that Cumulina died in her sleep last Friday of natural causes. The mouse was two years, seven months old -- about seven months above the average for her species.
The mouse made headlines when the results of the distinctive cloning technique of Dr. Ryuzo Yanagimachi's team were reported in the journal Nature in July 1998. The scientists turned out more than 50 carbon-copy mice using what was believed to be a more reliable cloning technique than the one used to create Dolly the sheep.
The nucleus of a cell from one mouse was injected through a tiny needle into an egg donated by a second mouse. The egg's original genetic material was removed. The donor nucleus came from cumulus cells, which surround the developing eggs in the ovaries. In fact, the technique employed is the reason for Cumulina's name. Cumulina raised two litters before "retiring." About eight months ago, Cumulina developed a skin tumor, common in aging mice, and the tumor was removed. "She had otherwise been healthy and active until several days before her death," the university said.