Clone is the ancient Greek word for twig. As any gardener knows you can produce a new plant by breaking off a side twig and shoving it in soil. There is a bit more to it than that, but you get the gist.
When the twig roots, you have a new plant. Unlike offspring raised from seed, the plant is identical in every way to the parent…. in other words a clone.
It is also the same genetic age as the parent/donor. The new plant is fully mature and will flower and fruit as soon as roots are established.
While this is great news for gardeners, me among them, it is not so great for animal clones. Just ask poor old Dolly the sheep. She was born at the same genetic age her ‘mum’ was -donor, actually- when the genes were harvested. And although a baby, she had the same remaining life expectancy. This is because aging is genetically controlled.
Telomeres are little tails on the end of each gene. They control the number of times cells replicate. Every time a cell replicates, part of the telomere breaks off until there is none left and the cell cannot make a new copy of itself. When cells can longer make new copies to replace old worn-out ones, the animal dies.
The ideal solution is to have cells that do not lose the telomere. In this way they become immortal, able to constantly reproduce. The good news is such cells already exist. The bad news is they are called cancer.
On that depressing note let me just finish by saying I am entirely with George Lucas. Attack of the Clones was a much punchier title.