How Did We Do It?
Huxley Paleozoo is a proud member of the International De-Extinction Alliance. The IDEA’s goal is to facilitate the de-extinction and reintroduction of extinct species, and the genetic assistance and repopulation of endangered ones. Almost none of our animals are cloned - the process of cloning requires living cells, and those are hard to come by for extinct animals. Creation of animals at Huxley falls under three categories: cloning, splicing, and engineering.
Cloning
On rare occasions, living cells are present. The process of cloning is relatively simple. DNA from the stem cell of a closely related species is removed using a refined descendant of the Beckham Zygote Extraction Procedure. DNA from the target animal’s cell is inserted, and the resulting zygote is incited to divide and inserted back into the relative. The embryo will develop inside the relative, which will eventually give birth to the target species. So far, only the Pyrenean ibex and a few species of frog have been successfully de-extincted this way; however, other members of IDEA have used this process to assist genetic diversity in extant species.
Splicing
For many recently extinct organisms, DNA still exists in remaining skin, scales, feathers, hair, and bones. This DNA can be spliced into the DNA of close living relatives to produce an organism that looks and acts like the target species. Let’s take the thylacine as an example. Resurrection biologists from Huxley Paleozoo and the University of New South Wales sample DNA from skins and bones in museum collections. Although the DNA exists, it’s fragmentary and not part of a living cell. This DNA is compared to and aligned with that of a stem cell from a close living relative, the Tasmanian devil. We synthesize identical strands to the thylacine DNA, and construct CRISPR-RNA to correspond with sections of the devil genome we wish to replace.
The synthesized DNA, CRISPR-RNA, and a Cas9 endonuclease enzyme enters the cell. Once inside, the CRISPR-RNA binds with the Cas9 and guides it to the section of devil genome we wish to change, Cas9 severs the beginning and end of this section from the DNA strands, and the cell repairs the DNA strand using the inserted thylacine DNA. The result is a Tasmanian devil cell with a segment of thylacine DNA spliced in. The process is repeated to insert as much thylacine DNA as we can into the cell. Afterwards, the cell is stimulated into dividing and developing into an embryo, and inserted into an artificial womb to develop into an animal that looks, acts, and functions like a thylacine - effectively, it is one.
Engineering
Huxley Paleozoo specializes in engineering extinct animals for which no DNA remains, and building on fragmentary chunks of preserved DNA. Often surviving extinct DNA is incomplete, and an extra “boost” is needed to make the organism more like the target. Huxley’s geneticists assist with this. After the successful dodo de-extinction (which incorporated very little preserved DNA), Huxley’s genetics team has taken engineering to the next level, engineering a whole organism without original DNA. Although we cannot legally divulge the entire process of engineering, we would like to make it clear that none of our pre-Pleistocene animals contain original DNA.