How do selective breeding, genome editing, and cloning differ as approaches to de-extinction?

De-extinction approaches differ significantly in their methodology, reliance on genetic material, and the extent to which they recreate an extinct species.1

• Selective Breeding (Back Breeding): This traditional approach uses the principles of selective breeding to crossbreed extant, closely related species in hopes of producing offspring that display the morphological traits of an extinct ancestor. It does not require the original species' DNA, but rather relies on historical descriptions and bone specimens. Because it lacks insight into the original animal's specific genetic makeup, the resulting animals often bear only a superficial resemblance to the extinct species.1

• Genome Editing: This synthetic biology technique involves adding or removing specific pieces of DNA in the genome of a living, related species. By reconstructing the genetic sequences of extinct species, scientists can identify specific genes to edit into the genomes of extant relatives, aiming to produce offspring with characteristics of the extinct species.12

• Cloning: Primarily centered on somatic cell nuclear transfer (SCNT), this method involves transferring the nucleus from a somatic cell of an extinct animal into an enucleated donor egg. The resulting embryo is then implanted into a surrogate mother of a closely related species. Unlike breeding or editing, cloning aims to create a genetic replica of the specific individual from which the cell was taken.1