Dolly the cloned sheep. Cause of death?

Question

I was told she died of old age although she wasn't old. (I know I'm a bit behind on news) It has something to do with protein in the cells which prevents cells to divide forever. I could be wrong but if so, what's that protein called?

Answer 1

Dolly died due to lung cancer caused by a viral infection. The same virus killed some of the naturally born sheep in the same stable. She was six years old. Expected life span is 11-12.

There is no definitive evidence that Dolly suffered from premature aging. She had arthritis in her hind legs but that could be explained by the fact that she was a celebrity. Her frequent visitors usually brought treats for her and she learned to stand on her hind legs to get them. She also was slightly overweight. Both probably contributed to her arthritis. This is not the same as the extreme gigantism frequently seen in cloned animals.

The initial report was that Dolly had shortened telomeres. However, her telomeres were measured in lymphocytes while she had an infection so it would be expected for telomeres to be shortened.

Telomeres are repetitive DNA sequences at the ends of chromosomes. They act as caps to protect the ends of DNA. The enzyme that catalyzes the lengthening of telomeres is telomerase. Telomerase is a protein+RNA complex that acts as a reverse transcriptase to add DNA to the end of chromosomes.

Answer 2

Dolly, the world's first mammal cloned from an adult, has died after being diagnosed with progressive lung disease. The Roslin Institute (near Edinburgh, England) confirmed that Dolly was put to death due to a variety of ailments. Dolly, born in 1996, appeared to be aging at a more rapid rate than normal sheep. In 1999, "scientists noticed that the cells in Dolly's body — cloned from a 6-year-old sheep — had started to show signs of wear more typical of an older animal." [1] According to an Associated Press article, "Some geneticists said the finding provided evidence that researchers could not manufacture copies of animals without the original genetic blueprint eventually wearing out."