“Take your stinking paws off me, you damned dirty ape!” Charleton Heston’s memorable line from the 1968 classic movie Planet of the Apes is about a world where chimpanzees, orangutans, and gorillas – genetically modified in the 2001 version of movie – enslave humans.
The original version was a story built around the racial intolerance, oppression, and animal experimentation of the late 1960s within a story of alternative evolution. The updated transgenic version is much more a parable of our post 9/11 times.
A transgenic animal is one that carries a gene that has been deliberately inserted into its genome, typically constructed using recombinant DNA methodology. The DNA usually includes other gene sequences to enable it.
In the May 2009 issue of Nature, a team at Japan’s Central Institute for Experimental Animals in Kawasaki detailed the genetic modification of marmoset monkeys. Scientists believe the monkeys produce useful animal models for human illnesses.
The team of scientists — led by Erika Sasaki and Professor Hideyuki Okano of Keio University School of Medicine — tested a technique they hope to use to produce animals with Parkinson’s, Huntington’s and other diseases, successfully inserting a gene from a jellyfish into marmoset embryos. The scientists modified a virus called a lentivirus to carry a jellyfish gene known as green fluorescent protein (GFP). The jellyfish gene –- originally isolated from the jellyfish Aequorea victoria –- produced GFP in the marmoset tissues.
According to the Washington Post, the researchers used the genetically engineered virus to insert the jellyfish gene into 80 marmoset embryos, which they then transferred into the wombs of 50 females. Seven pregnancies resulted in five offspring, four of which showed signs of the jellyfish gene in their hair roots, skin, blood cells and other tissues.
Under ultraviolet light, the skin on the soles of their feet – looking like the skin of Dr. Seuss’ Grinch when he tried to steal Christmas – turned green and glowed in the dark under ultraviolet light (UV). The researchers didn’t expose their entire bodies to the UV because “it might hurt their eyes.”
And no, the marmosets didn’t end up looking like some strange SF monkey-jellyfish hybrid.
It’s notable that a rhesus monkey named ANDi became the world’s first transgenic primate in 2001. He was genetically modified as an embryo, with a gene from a jellyfish that should have made him appear luminescent green. It failed to turn him green or make him glow in the dark.
Close cousins to rhesus monkeys, marmosets are the smallest members of the primate group –
but not as closely related to humans as rhesus monkeys. Marmosets make better research subjects than rhesus monkeys because they reproduce far more quickly. "Usually marmosets have 4 to 6 babies in a year," says Dr. Sasaki. "We can expand lots of animal colonies if we establish a transgenic founder marmoset."
Transgenic mice –- with human DNA inserted –- are widely used in research. For example, transgenic mice expressing the human gene for the polio virus receptor can be infected by the polio virus and develop paralysis and other pathological changes characteristic of the disease in humans.
Under ultraviolet light, the skin on the soles of their feet – looking like the skin of Dr. Seuss’ Grinch – turned green and glowed.
"However, in many cases, research results obtained in mice cannot be directly applied to humans because of the many physiological, anatomical and histological differences between mice and humans, which are evolutionarily distinct," says Keio University’s Okano.
A study commissioned by Great Britain’s Royal Society describes the breadth of scientific research involving non-human primates. This research includes drug pre-clinical toxicology studies, studies of infectious disease (such as HIV/AIDS and hepatitis), studies of neurology and neuroscience, behavior and cognition, reproduction, genetics, and xenotransplantation. Non-human primates are generally intentionally bred for use in research laboratories, although some are caught in the wild. Approximately 65,000-70,000 non-human primates are used each year in the United States and European Union.
In December 2006, an inquiry chaired by Sir David Weatherall, emeritus professor of medicine at Oxford University, concluded that there is a "strong scientific and moral case" for using primates in some research. This is clearly a sticky issue for many animal rights groups.
The marmoset experiment could lead to crucial insights into many ailments such as Parkinson’s, Huntington’s and other diseases – and provide invaluable ways to test new treatments. But it also highlights the possibility of inheritable genetic modification in humans. Most industrialized nations – including Japan – prohibit human-inheritable genetic modification. The United States currently has no such law.
"It would be easy enough for someone to make the leap to trying this on humans," said Lori B. Andrews, who studies reproductive technologies at the Illinois Institute of Technology’s Chicago-Kent College of Law. "If you make this kind of change, it’s passed on to all future generations."
She goes on to say that the transgenic approach raises ethical questions of whether it’s desirable to engineer traits in humans, “creating a society of genetic haves and have-nots.”
Some worry that such work could have additional implications, such as potentially blurring the line between species – an extreme SF example being the human-ape hybrids in the 2001 remake of The Planet of the Apes.
“The creation of a transgenic marmoset underlines the need for scientists and policy makers to reject human inheritable genetic modification,” says Marcy Darnovsky, executive director of The Center for Genetics and Society.
"The development of techniques to modify the genes of primates across generations raises the issue of human inheritable genetic modification,” she continues. “Responsibly conducted animal research holds potential to reduce suffering, but there is no justification for human inheritable genetic modification."
Better monkeys? It’s doubtful that monkeys with underpaws that glow green in the dark are better adapted to their environment, unless they’re going to be used for nighttime reconnaissance missions in Iraq or Afghanistan.
And no, we’re not likely to see a planet of green marmoset monkeys genetically bred for human-level intelligence –- although, Charleton Heston probably would have found them much cuter than the prosthetically-enhanced actors he discovered when his spacecraft crashed on a parallel universe Earth run by apes.
While transgenic research involving marmosets rather than mice may help shed light on more effective treatments for Parkinson’s, Huntington’s and other diseases, it does raise questions about animal experimentation – one of the major themes of the original The Planet of the Apes.
Perhaps a bigger ticket question, however, is human inheritable genetic modification – building better humans through the insertion of gene sequences and DNA manipulation. The debate over this issue during the 21st Century is likely to be as large – or larger – than Roe v. Wade is today.