Cloning

When you hear the word "cloning," you might imagine science fiction — but cloning happens in nature all the time! When a strawberry plant sends out runners that grow into new plants, or when identical twins are formed from a single fertilised egg, these are all examples of natural cloning.

In science, cloning refers to producing genetically identical copies of organisms through asexual reproduction or laboratory techniques. Because clones inherit all their DNA from a single parent (rather than two), they are genetically identical to that parent.

There are two broad categories of cloning:

• Natural cloning — occurring without human intervention (e.g., identical twins, asexual reproduction in plants and animals)
• Artificial cloning — performed deliberately in a laboratory setting (e.g., tissue culture, somatic cell nuclear transfer)

Nature produces clones regularly. Understanding natural cloning helps us appreciate that the process is not as unusual as it might first seem.

Examples of natural cloning:

• Identical twins (monozygotic twins): A single fertilised egg (zygote) splits into two embryos early in development. Both embryos carry identical DNA. This is a rare but well-known example of natural cloning in humans.
• Vegetative reproduction in plants: Many plants reproduce asexually by producing runners (stolons), bulbs, tubers, or rhizomes. Each new plant produced this way is a genetic clone of the parent plant. Examples include strawberries, potatoes, and daffodils.
• Budding in animals: Some animals, such as hydra (a tiny freshwater invertebrate), reproduce by growing a bud that breaks off and becomes a new individual — genetically identical to the parent.
• Parthenogenesis: In some species (e.g., certain insects, reptiles), unfertilised eggs can develop into new organisms without being fertilised — producing clones of the mother.