Because cloning is bringing biological science right into the headlines. And if you don’t know your DNA from a packet of doggy drops you can hardly take the conversation by the scruff of the neck.
However, this is one situation where a little knowledge can be a very helpful thing...
Just a bit of literary background first of all.
Because it always sounds impressive when you can give the derivation of a word. Especially when that derivation is from classical civilisation...
"Clone/cloning/to clone" happily are all words that fall into this category. They come from the Greek for "twig". Which makes sense if you stop thinking of a twig as something "small and woody" and think of it as "an offshoot from the original branch, which retains all the characteristics of the main tree… " (Not that the Greeks knew about genetic engineering, needless to say).
Despite the media bonanza surrounding Dolly the Sheep, you can then announce that it’s actually not that hard to create a clone….
When challenged, you can explain that if you take a cutting from a plant, that new plant will be a clone of the first. And if you cut a worm in half, then it will regrow into two separate worms, which are clones of each other. The results in each case may not be visually identical to the parent - but the point is, they will be genetically identical, because there’s been no other ’parent’ involved.
A common misconception about cloning is that, if, say for example, Tony Blair decided to create twenty clones of himself - which he has never said as far as we’re aware, but hey this is just an example - they would all be identical to him, and be able to staff the Cabinet after the next reshuffle.
But this is not the case at all. Any clone begins with a single cell. Therefore, IF human cloning ever went ahead, it would take nine months for a clone be born - and 47 to grow up into a replica of today’s PM. By which time the original of course would be well into his 90s….
So you’ll never be able to grow yourself a twin - and therefore the film ’Multiplicity’ is not scientifically rigorous. Just in case you thought it was!
The process which created Dolly is called ’nuclear transfer’. Basically the DNA within an egg cell is replaced by the nucleus - including the DNA - from the cell of the animal you wish to clone. The cell from the ’clonee’ animal then reverts to the behaviour of an embryonic cell, dividing and growing into an embryo without the influence of genetic material from any ’father’.
The DNA which is the blueprint for the characteristics of the grown clone does all come from the mother’s cell - but there is another sort of DNA involved, which not a lot of people - or news reporters - know about ….
This is the ’mitochondrial DNA’ in the cell. The mitochondria in a cell produces the energy the cell needs to do all it’s business, eg replicating and growing, so it’s clearly key to the process too … And this does not come from the cloned cell, it comes from the owner of the egg cell. So technically, there are still two forms of genetic material within a clone. Not a lot of people know that …
Although most clones to date have been female - with Dolly of course the most famous example - they don’t have to be. It’s thought to be no harder to create a male clone, but the reason why many labs concentrate their efforts on producing female clones, is because companies backing the work are interested in cloning animals that could be genetically engineered to produce useful proteins in their milk.