Dolly has Arthritis!

Dolly has only been a clone for just 5 years, and already she has arthritis in her left hind leg, hip, and knee.  Researchers have worried that this might happen, as she was copied from the cells of a six-year-old sheep.  Why is this?  Sheep do not usually get arthritis at this age, or get it in those particular joints.  It seems as though cloned animals will be more prone to get diseases.  This diagnosis was "very disappointing", say Dr. Wilmut, the leader of the team to clone Dolly.
There have always been signs that cloned animals are more vulnerable to heart and breathing problems, obesity, and deformity.
However, this diagnosis didn't come as a total surprise.  In 1999, reports showed that Dolly's cells were older than her birth age.  In fact, Dolly could have been six years old the moment she was born.  Then Dolly would really be 11, and a normal lifespan for a sheep is 12-15 years.
Studies have found that the telomeres (tail on the end of a chromosome that keeps the genetic information inside) on Dolly's cells and the cells of two other cloned animals are shorter than those on regular sheep of the same maturity.  In lab studies, telomeres become smaller after each cell division.  After many divisions, the telomeres wear down to 'unstable stubs' and will discontinue division, break down, or die.
While no-one can blame Dolly's short telomeres or the cloning process for her arthritis, investigations have shown that people with rheumatoid arthritis also have shorter telomeres.
Cells being cloned won't necessarily be reset to day one when transferred into the case that becomes the clone.  Some incomplete genetic programming in the cloning process may be the problem here, but it may also depend on the creature being cloned or the method used clone a creature.