backtop


Print 71 comment(s) - last by fflintstone.. on Feb 11 at 5:13 PM


The tasmanian tiger, Thylacinus cynocephalus, seen here at the Washington DC zoo in 1902, has been extinct since 1936.  (Source: Wikipedia)

The mouse embryo, seen here, is now part thylacine -- it contains thylacine DNA which will effect its muscle and cartilage growth.  (Source: Andrew Pask and Richard Behringer)

Russian researcher Sergei Zimov is building a vast 160 sq km "Pleistocene Park" in northeastern Siberia near Alaska. He hopes to one day populate it with wooly mammoths and sabertooth tigers.  (Source: BBC News)
By injecting DNA sequenced from an extinct species into a mouse embryo, scientist have delivered a proof-of-concept, which could one day lead to full cloning of long-extinct species

Cloning extinct species has been a long standing dream of mankind.  Well, long standing since the 90s at least, when the movie Jurassic Park stole the imagination of audiences worldwide with a fictitious story in which scientists use DNA extracted from long dead dinosaurs to resurrect the beast through cloning (with disastrous results).  Since the movie, cloning science has advanced at a steady pace, and there has been increasing interest within the scientific community in cloning extinct creatures.

While it seems unlikely that dinosaur DNA pristine enough to produce a full genome map would ever be found, it would be reasonably easy to sequence other extinct creatures genomes such as the dodo, Neanderthals, wooly mammoths, and other more recent critters which researchers have recovered soft tissue samples (bone marrow, skin, etc) from.  However, such dreams were often scoffed at and remained the realm of pseudoscience.

They were derided -- until now.  In an exciting, successful new experiment, researchers at the University of Melbourne report that they have taken DNA from the extinct thylacine, commonly known as the Tasmanian tiger, and inserted it into a mouse embryo which continued to grow with the thylacine gene in place.  The process represented the first time DNA from an extinct creature was inserted into an embryo, effectively bringing "back to life" in part the extinct species.

Dr Andrew Pask, who led the research, says the experiment was the first time DNA from an extinct species has been successfully used "to induce a functional response in another living organism".  Professor Marilyn Renfree, a member of the team, states, "For those species that have already become extinct, our method shows that access to their genetic biodiversity may not be completely lost."

The findings of the team will be reported in the international science journal PLoS ONE this week. 

The Tasmanian tiger, whose scientific name is Thylacinus cynocephalus or thylacine for short, is an extinct marsupial from Australia that looked like a wolf.  The last surviving member of the species died in captivity at the Hobart Zoo in 1936.  The gene was extracted from tissue samples of flesh preserved in ethanol, which were donated by the Museum Victoria in Melbourne Australia.  The DNA was verified to be thylacine, and then was injected into the developing mouse embryo.

The gene injected was the thylacine Col2a1 gene, which controls cartilage and bone growth.  The mouse embryo was selected, partially because mice have a similar gene, also labeled Col2a1.

Dean of Science at the University of New South Wales, Mike Archer, is leading a project that aims to fully clone extinct animals, but he warns that success remains far off. He commented on the developments, stating, "The next question then is, well what if you did that with the whole of the DNA of the thylacine?  Could you in fact bring back a thylacine? Technically I think this is pretty difficult at the moment but on the other hand this is one very significant step in that direction and I'm delighted."

Despite the steep challenge, Professor Archer isn't giving up.  He states, "I'm personally convinced this is going to happen. We are working on a number of projects like this. I've got another group working on another extinct Australian animal and we think this is highly probable."

Aside from possibly leading to clones of extinct animals, the breakthrough also may yield scientific gains in biology and medicine.  Professor Richard Behringer, Deputy Head of the Department of Molecular Genetics, M.D. Anderson Cancer Center, at the University of Texas, says, "This research has enormous potential for many applications including the development of new biomedicines and gaining a better understanding of the biology of extinct animals."

Several groups are working to make real life Jurassic Park-style exhibits with cloned animals.  Some like a team in Japan are focusing on finding frozen gametes from ice age animals, while others are focusing on more traditional cloning

Perhaps most ambitious is the Pleistocene Park currently being built in northeast Siberia by Sergei Zimov.  Zimov introduced a grassland ecosystem along with 100 large mammals including
reindeer, horses and moose.  He plans on eventually introducing to the park wooly mammoths, extinct saber tooth tigers and prehistoric bears; all cloned of course.  On the possible threat of cloned tigers he states, "OK, so one or two people will be killed, like in India, but far more will die of alcohol in this place than from tigers."

While Zimov and others have thus far not revived any extinct species, advances in cloning may one day make their dreams a reality.  And with the new Australian breakthrough, that day seems to have come much closer.



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: WRONG
By tmouse on 5/21/2008 10:10:16 AM , Rating: 2
Ok here are the facts:

They did not clone anything in any way, shape or form.
They sequenced a very small fragment (264 base pairs) from an enhancer element from the proa1(II) collagen gene. They compared the sequence to known sequences in genbank and found it different enough from human and mouse sequences to be sure it was not an artifact. They made a reporter gene construct basically an enzyme that can provide a blue staining of the tissues it’s expressed in under the regulation of this enhancer element. They created a transgenic mouse with it and observed the "stain" was only where it was expected to be. It is really only a proof that the DNA was in good shape and that there was no PCR artifacts when they amplified it for sequencing. Who knows if other animals that have never been sequenced (either different species or even individuals) could have this sequence naturally. The gene was chosen because it is VERY highly conserved. Its stretching it a bit to even say they produced chimeric cells, definitely not cloning. I’ve made dozens of transgenic animals and I would not say they were Human/Mouse chimeras (although some would I guess) and No one I know of would say it’s a step towards cloning a human. Rather than a chimeric cell it’s really closer to a somatic cell hybrid (although that is the fusion of two genomes in one cell. I respect Richard Behringer, he is an important person in transgenics but this is really FAR more flash than substance.


"You can bet that Sony built a long-term business plan about being successful in Japan and that business plan is crumbling." -- Peter Moore, 24 hours before his Microsoft resignation

Related Articles
South Korean Firm Will Clone Your Pet
February 15, 2008, 4:39 PM













botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki