Cloning organisms and genes

Reproductive cloning makes a whole organism that is genetically identical to another. Embryo splitting divides one early embryo into twins; somatic cell nuclear transfer (SCNT), the method behind Dolly the sheep, puts a body cell’s nucleus into an emptied egg. Step through each method and watch how the copy is made, then compare gene cloning, which copies a single gene rather than an organism.

Cloning methods, step by step Embryo splitting · step 1 of 5

Step through slowly: each method’s steps play in order

An egg is fertilised (IVF) to make one zygote

Method and step

Embryo splitting SCNT (Dolly) Gene cloning

DNA comes from One embryo

Result Identical twins

Therapeutic cloning uses somatic cell nuclear transfer (SCNT) to create embryonic stem cells for research and potential treatments — the embryo is never implanted, so no organism develops. Reproductive cloning (like Dolly) uses the same SCNT technique but implants the embryo to produce a live animal. The biology is identical; the ethical dividing line is whether you let development continue. Dolly proved mammals could be cloned from adult cells, but success rates remain below 5% — most embryos fail, and survivors often have health defects. Meanwhile, natural clones (identical twins, asexual organisms like strawberry runners) happen all the time without any technology, and far more reliably than SCNT.

Know This

Reproductive cloning (embryo splitting or SCNT) makes a whole organism with the same nuclear DNA as its twin or its donor; SCNT is still inefficient and raises welfare concerns. Gene cloning copies one gene in bacteria, not an organism, and natural clones such as identical twins arise without any technology.

Cloning organisms and genes: interactive biology widget

A whole new animal can start from one nucleus