What comes to mind at the word 'clone'? Researchers in white coats, glass tubes, Dolly the sheep, most likely — something cool and artificial about it. And yet the home of this word is not a laboratory. It is a field.
A Greek word meaning twig
In 1903 the American plant physiologist Herbert Webber proposed a new word. He needed a name for groups of plants multiplied without passing through seed — by cuttings, by grafts, by bulbs. What he chose was the Greek klōn (κλών).
The word means 'twig'. More precisely, it named a length of branch broken off for propagation.
Webber explained it this way: such plants are not individuals in the ordinary sense, but transplanted parts of the same individual. Break off a branch and plant it, and no new life is born — that same tree has simply moved one more piece of itself.
Dolly the sheep was born 93 years later, in 1996. So this was a word that trees used long before sheep did.
but the name of a broken-off twig.
A seed does not take after its parent
So why did people trouble to break off branches when seeds were right there?
The answer lies in a line left by the Greek scholar Theophrastus around 300 BC. Of the apple tree he wrote: seedlings of apples produce an inferior kind — acid instead of sweet; and this is why men graft.
Twenty-three centuries ago they already knew it: plant the seed of a delicious apple and no delicious apple follows.
The reason lies in how a seed is made. Into a seed the traits of both parents are mixed. As siblings resemble one another without being the same, trees raised from seed come out each its own. Some match the parent; many fall far short.
So if you have gone to great trouble to find one delicious apple tree, there is only one way. Do not plant its seed — cut its branch and carry it. Every apple tree of one variety we eat today, whatever its name, spread by branch from that first single tree. A variety of apple is, in truth, one tree.
A clay tablet four thousand years old
How old this craft is comes up out of the ground.
On a cuneiform tablet from Mari in Mesopotamia there is a record of bringing in grape budwood. It dates to around 1800 BC — nearly four thousand years ago. Traces of similar age are found in China, and both Aristotle and Theophrastus discussed grafting.
What is interesting is which trees came under cultivation first.
Figs, grapes, pomegranates, olives, dates — these were the first fruit trees to pass into human hands. They share one thing: break off a branch, set it in the ground, and it roots readily. So whenever a good tree was found, it could be multiplied at once.
Apples, pears, and plums came later. Their cuttings do not root easily. Taming these trees called for another craft, and out of that came grafting — if it will not root, set it upon another tree that already has roots.
Humankind, one might say, invented grafting in order to have the apple.
And in fact, we do it at home
If you have read this far you may already have guessed. A clone is no special technology. We do it all the time, in everyday life.
Cut a stem from a houseplant, stand it in a glass of water, and white roots appear within days. That is a clone. When we plant potatoes we bury not seed but a piece of potato with an eye on it. Garlic, too, is planted as a clove, not a seed. Sweet potato is set from a cut shoot, and a strawberry makes a new plant wherever its runner touches down.
All of these are clones. What our grandmothers did in the yard is exactly what Webber gave a name to.
The banana we eat has no seeds at all. With no seed there is no way to breed it. Every banana plantation in the world is kept going by transplanting the pups that rise from the roots. To eat a banana is, in effect, to share one banana plant.
Nature does it on its own as well. A bamboo grove often turns out to be a single individual joined underground, and a certain aspen colony in the United States is known as one individual of tens of thousands of stems risen from a single root.
And the warning four thousand years left behind
A shadow came along with this old craft. For to be identical is to be identical in weakness too.
Until the mid-twentieth century the banana the world ate was a variety called Gros Michel — sweeter and better scented than today's, they say. Then a fungal disease went round, and plantations fell one after another across the world. All were the same clone, so where one was taken the next was taken also. Gros Michel vanished commercially, and people moved to another variety that withstood the disease. That is today's Cavendish. And the Cavendish, now, is being run down by a new fungus of its own.
There is a more painful story. The Irish famine of the 1840s. Ireland then depended almost entirely on a few potato varieties for food, and potatoes too are clones, so they were nearly identical. When blight came there was nothing to stand in its way; a million died of hunger and a million left their home.
A clone is the craft of repeating the best thing perfectly. But hidden inside the word 'perfectly' was this: that the one weakness of that one thing is repeated perfectly too.
What a single twig means
Looked back upon, there is something rather fine in this story.
For four thousand years, whenever people met a good tree, they broke off a branch and carried it elsewhere. Where that branch took root, the tree did not die but went on. The apple tree Theophrastus saw, the grapevine written on the tablet — they came to us that way. Webber only gave a name to that old wisdom, and the word he happened to choose was 'twig'.
And those four thousand years taught one thing more: repeat the best one, but do not fill everything with that one. What the banana and the potato paid was the tuition for that lesson.
In the planting of trees these two always travel together — the wish to carry the good thing onward, and the caution not to stake everything on it. Within that plain little name, a single twig, both of them are in fact contained.
'Clone' was originally a Greek word meaning 'twig'. For four thousand years, whenever people met a good tree, they broke off a branch and carried it onward — because a seed does not take after its parent, while a branch repeats that very tree. Yet to be identical is to be identical in weakness too. Carry the best one onward, but do not fill everything with that one — the tuition for that lesson was paid by the banana and the potato in our stead.