There are many technical problems to achieving the rebirth of Dinosaurs as seen in Jurassic Park. However, bringing back the Woolly Mammoth, Saber-Tooth Tigers and Neanderthal from the Pleistocene epoch seems possible. The Pleistocene is the epoch from 1.8 million to 10,000 years BP covering the world's recent period of repeated glaciations.
How to Bring An Extinct Species Back
* Well-preserved DNA
* Several billion DNA building blocks
* A suitable surrogate species
* Some seriously advanced technology
* You can also cheat by taking similar living species and modifying it to be like the extinct one. It is also technically difficult to modify a very large number of genes.
How are we doing on Mammoth, Saber-tooth and Neaderthal DNA?
Scientists have completed a first draft version of the Neanderthal genome. Neanderthals were the closest relatives of currently living humans. They lived in Europe and parts of Asia until they became extinct about 30,000 years ago.
Woolly Mammoth DNA has been mapped as well.
All sabre-tooth mammals lived between 33.7 million and 9,000 years ago, but the evolutionary lines that led to the various sabre-tooth genera started to diverge much earlier. There are permafrost-preserved specimens of Saver-tooth cats that would be a good source of DNA. If we could obtain a genome, a close living relative of the sabre-tooth, the African lion, should be a good egg donor and surrogate mother.
New Scientist has an analysis of ten extinct species that could be brought back.
We Have Briefly Brought Back an Extinct Goat and Cloned Dead Animals
Scientist were able to use frozen skin in 2003 to clone a bucardo, or Pyrenean ibex, a subspecies of Spanish ibex that went extinct in 2000. The latest attempt involved the creation of 439 ibex-goat hybrid cloned embryos made by inserting the cell nuclei of the ibex's skin cells into the egg cells of domestic goats which had their own cell nuclei removed. Of these cloned embryos, 57 were transferred into surrogate mothers and seven resulted in pregnancies, but only one goat gave birth and the newborn clone died after seven minutes as a result of lung deformities.
Human Cloning Appears to be Feasible
Robert Lanza notes that a human nucleus inserted into a different human’s egg cell appears to develop normally. “We show for the first time that the same genes turned on in normal human embryos are the same genes turned on in human clones” [Wired News], he says. If Lanza’s study holds up to further scrutiny, it will mean that there are no technical barriers to therapeutic or reproductive cloning. Which means, some experts say, that it’s just a matter of time before someone tries to make a genetic copy of themselves.