Poll Dorsets are a common Scottish breed of white sheep. Another popular breed of sheep is the Scottish blackface wchich is similar to a Poll Dorset except it has a black face and a larger body. Both breeds were used in the Dolly Experiment. Wilmut and Campell removed an egg cell from a female adult blackface sheep. and a nucleus from a Poll Dorset's ovine mammary gland epithelial (OME) cell was inserted into the egg. After this nucleus transfer procedure, the egg develops into an embryo and is implanted in the blackface's uterus.
A very large number of embryos were produced but only one single lamb named Dolly was born.
Although Dolly was the first mammel to be successfully cloned from an adult cell, she died at the age of six on February 14, 2003. Scientists were worried that Dolly would develop medical disorders because her cells had abnormally short telomeres. Despite this, Dolly gave birth to six healthy lambs. At birth Dolly's genome was already middle-aged.
Wilmut's team analyzed Dolly's short telomeres in 2000, but the effects of these telomeres are still unknown. In 2001 Dolly developed arthritis in her left knee and hip joint. Scientists are stillnot sure if the abnormal telomeres caused arthritis.
Dolly =]
