Geek Trivia: How many parents did Dolly the cloned sheep actually have?

Most modern versions of sci-fi clones don't have just one parent -- they have several -- and this goes for the world's most famous cloned mammal: Dolly the sheep.

Contrary to what some extraordinarily awful science-fiction movies may have taught you, cloning technology does not (yet) allow you to take any random cell from any organism and grow an exact copy of that lifeform in a petri dish. And even if it did, we're a long way from managing the cloning process on anything approaching an industrial scale. Case in point: Dolly the sheep, the poster child (or, lamb) for modern cloning.

Dolly was the first mammal successfully cloned using nuclear transfer from an adult somatic cell to reach adulthood. If that sentence seems highly specific, that's intentional, as there are several different ways to skin a cat in the cloning world (though presumably none of them involve actually skinning cats). The description above is a relatively accurate scientific label for classical sci-fi cloning, which requires far more than just invoking the word cloning.

In its broadest biological usage, cloning means creating a new organism that is genetically identical to its progenitor. Bacterial reproduction is, in a literal sense, natural cloning, as is most asexual reproduction. Molecular cloning refers to the reproduction of individual organic molecules, usually DNA or RNA, which is a fairly well understood and replicable laboratory process. The same goes for cloning individual cells -- particularly pre-adult cells.

It is relatively easy to harvest embryonic cells and coax them into making more embryonic cells, as happens during some in vitro fertilization procedures. After all, embryos are primed to replicate and grow into adult organisms. Cloning somatic cells -- as in non-embryonic, non-reproductive, functionally specified cells -- is a much more difficult feat, but is also fairly well understood. Somatic cell cloning is the basis for many new skin graft therapies, where new skin patches are cloned from a few samples of donor skin cells.

The trick is taking a somatic cell from an adult organism and getting it to turn into another viable, full-grown adult copy of that entire organism. The leading technique for such cloning, known as somatic cell nuclear transfer, requires harvesting cell types from multiple donor organisms. Thus, most modern versions of sci-fi clones don't have just one parent -- they have several -- and this goes for Dolly the cloned sheep.


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By Jay Garmon

Jay Garmon has a vast and terrifying knowledge of all things obscure, obtuse, and irrelevant. One day, he hopes to write science fiction, but for now he'll settle for something stranger -- amusing and abusing IT pros. Read his full profile. You can a...