Cloning's not a new idea: the Greeks had a word for it centuries ago

URL: http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v408/n6815/full/408905a0_fs.html

Date accessed: 06 February 2001

Nature 408, 905 (2000) © Macmillan Publishers Ltd.

21/28th December 2000

Sir – The term 'cloning' originates from the Greek word clonos, meaning 'twig'; clonizo is the verb 'to cut twigs'. A kind of cloning has been widely used in agriculture for centuries: by this process a new tree is created from an adult tree's twig without use of its seed, analogous to the cloning of mammals from adult cells.

The idea that cloning is also possible in humans also evolved in ancient times: it was realized that the principles of reproduction did not lie in the reproductive organs or seed.

Joannes Philoponus, an Alexandrian philosopher of the sixth century ad, commenting on Aristotle's writings, observed: "If someone cuts a twig from a walnut tree in Athens and plants it in Patras [200 km away], two or three years later it will bear nuts that are the same in every aspect, in size and taste and colour and every other character, with the ones from the walnut tree in Athens. . . . So, if the resemblances between the plants do not originate because the seed comes from the entire body, as it was proved, but for some other reason, which [reason] he reveals later, the same applies to animals as well."

Philoponus used the word clados for 'twig', which is synonymous with clonos.

He was trying to find a reason for the resemblance between parents and children. Although he made many mistakes, he did correctly imagine the existence of some minimal part of the animal's body that contains all the information for the creation of the animal.

His thoughts were inspired by Aristotle. In his book On Animal Generation Aristotle proved that the information for the creation of an animal existed in all parts of the body but that, in opposition to other thinkers' beliefs, the semen did not come from the entire body in order to contain this information.

"Children are like their more remote ancestors from whom nothing has come," Aristotle wrote, "for the resemblances recur at an interval of many generations, as in the case of the woman in Elis who had intercourse with an Ethiop; her daughter was not an Ethiop but the son of that daughter was. The same thing applies also to plants."

Aristotle, many centuries before Mendel, referred to the properties of the propagation of genetic information in plants and humans. The fact that "resemblances recur at an interval of many generations" is probably Aristotle's most important observation in this regard, implying that certain characteristics do not have to be expressed to the next generation to be perpetuated.

"If again something creates this composition later," Aristotle continued, "it would be this that would be the cause of the resemblance, not the coming of the semen from every part of the body."

Today, we know that Aristotle's "something" is DNA. Aristotle understood that something undifferentiated exists that has the potential to become a plant or an animal, and that the semen is just the carrier of that potential.

Philoponus probably used a walnut tree rather than, say, an olive tree, intentionally. The word karyo (nut) also meant 'testicle', then as now, and is still used today in words such as karyotype and karyokinesis.

Using Aristotle's ideas about the transmission of information from parent to child, Philoponus suggested that a kind of cloning is possible in animals. Although the use of the term 'clone' by Philoponus is a very primitive example, it is the first reported use of the word for such a process.

One would not expect a thinker from the sixth century ad to be able to clone sheep, but, as with many other modern achievements, the principle was cultivated in the minds of the ancients.

A. A. Diamandopoulos
Chorio Romanou, 26500 Patras, Greece

P. C. Goudas
Chorio Romanou, 26500 Patras, Greece

Category: 33. Cloning