If you hear from sci-fi (science fiction) story about when the villains get the superhero DNA sources like hair, blood and skins, so the villains clone it and make the world chaos? It seems like the very easy to clone organism, just get their DNA stretch. But in reality, is not just an easy step.
Another example,sci-fi writers have been resurrecting Neandertals in novels for decades, imagining what it would be like to see and communicate with another species of human. So once the idea of sequencing the Neandertal genome became more than a glimmer in a paleogeneticist’s eye, some have asked, “Could we, should we, would we, bring this extinct human species back to life?” After all, biologists are trying to bring back the woolly mammoth by cloning. But for both technical and ethical reasons, experts say, bringing back a Neandertal is a pipe dream.
Could we do it? Robert Lanza laughed at the thought. Chief scientific officer for Advanced Cell Technology in Worcester, Massachusetts, he and his colleagues have cloned species from cows to goats to mice and extended their efforts to include endangered species and human embryos. But cloning Neandertals is fantasy, says Lanza. “You can’t clone from stone, and you can’t clone from DNA that has been destroyed from weather and the elements,” he points out.
From the statement above, to clone an organism is not simply get their DNA, a lot of factor must be considered. We are specific in cloning Neandertals from their stretch of DNA. Like Lanza says, we can’t cloned from from DNA that destroy by weather and element because of the DNA stretch that we get has a lot of missing gap in their genome.
Even we have their complete genome, it wouldn’t be enough. DNA itself doesn’t tell the whole story. Chemical modifications to the genome, the way chromosomes arrange in the nucleus, and maternal components in the egg all play a role in translating a genetic blueprint into a viable individual. “It’s not just the DNA; there’sa lot else going on,” says Lanza. None of that information is even available for Neandertals.
Then, too, cloning doesn’t typically start with a genome; it starts with two cells. One cell provides a nucleus (with DNA inside), and one is an egg cell, most often of the same species, whose DNA has been removed. The nucleus is then transferred to the egg, sometimes by fusing the two cells. “If you have just got DNA, you are asking an enormous amount of the oocyte that you are going to put the DNA into,” explains Ian Wilmut, who cloned Dolly the sheep and now works at the University of Edinburgh in the United Kingdom. “It has to reform the nucleus and reprogram [the DNA].”
That leads to the next problem: What species’ egg would play host to this DNA? The obvious candidate would be a modern human egg, but they are notoriously fickle and don’t take well to nuclear transfer, even of modern human DNA. “There’s something different about primates that we haven’t identified,” says Wilmut. “[Cloning] works very poorly.” And incompatibilities between Neandertal DNA and the human egg might further diminish the chances of a viable embryo.
Molecular geneticist George Church of Harvard University has proposed another approach: modify the DNA in a human cell line to resemble the Neandertal. “This is a daunting task,but with future technological developments and enough time and money, it may be possible,”says Adrian Briggs, who worked on the Neandertal genome sequence and is about to join Church’s lab. In theory, one could convert a human or chimp genome to a Neandertal genome—base by base—while it is still nicely nestled in a stem cell, then clone it. But there’s on the order of a million differences between the Neandertal and human genomes, and the more changes needed, the greater the risk of
introducing errors.
If, somehow, a viable embryo were produced, this developing chimera would need a surrogate mother. What species would that mother belong to? Again, the obvious choiceis a human, but no one knows whether a modern woman’s biochemistry would be compatible with that of a Neandertal fetus. And is it ethical for a human surrogate mother to birth a Neandertal baby? It’ll bring ethical issues. Once cloning works well in a variety of animals and stem cell–derived organs become commonplace, “I think the resistance to it will disappear,” he says.
I would like to share may be some other approach based on the research of J. Craig Venter, who for 15 years, J. Craig Venter has chased a dream: to build a genome from scratch and use it to make synthetic life. Now, he and his team at the J. Craig Venter Institute (JCVI) in Rockville, Maryland, and San Diego, California, say they have realized that dream.
They describe the stepwise creation of a bacterial chromosome and the successful transfer of it into a bacterium, where it replaced the native DNA. Powered by the synthetic genome, that microbial cell began replicating and making a new set of proteins. (You can read further at www.sciencemag.
org/cgi/content/abstract/science.1190719)
This is “a defining moment in the history of biology and biotechnology,” says Mark Bedau, a philosopher at Reed College in Portland, Oregon, and editor of the scientific journal Artificial Life. “It represents an important technical milestone in the new field of synthetic genomics,” says yeast biologist Jef Boeke of Johns Hopkins University School of Medicine in Baltimore, Maryland.
May be the finding can help in cloning the Neandertals but this is bring the ethical issues. “We do not—and
should not—create human beings just to satisfy our scientific curiosity,” says Pääbo, pointing out that Neandertals are a species of human.
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