by Michio Kaku
Even more interesting is the HAR1 region of the genome, which contains only 118 letters. In 2004, it was discovered that the crucial difference between chimps and humans in this region was just 18 letters, or nucleic acids. Chimps and chickens diverged 300 million years ago, yet their base pairs in the HAR1 region differ by only two letters. What this means is that the HAR1 region was remarkably stable throughout evolutionary history, until the coming of humans. So perhaps the genes that make us human are contained there.
But there is an even more spectacular development that makes Dawkins’s proposal seem feasible. The entire genome of our nearest genetic neighbor, the long-extinct Neanderthal, has now been sequenced. Perhaps by computer analysis of the genome of humans, chimpanzees, and Neanderthals, one might use pure mathematics to reconstruct the genome of the missing link.
BRING BACK THE NEANDERTHAL?
Humans and the Neanderthals probably diverged about 300,000 years ago. But these creatures died out about 30,000 years ago in Europe. So it was long thought that it was impossible to extract usable DNA from long-dead Neanderthals.
But in 2009, it was announced that a team led by Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig had produced a first draft of the entire Neanderthal genome, analyzing the DNA from six Neanderthals. This was a monumental achievement. The Neanderthal genome, as expected, was very similar to the human genome, both containing 3 billion base pairs, but also different in key respects.
Anthropologist Richard Klein of Stanford, commenting on this work of Pääbo and his colleagues, said that this reconstruction might answer long-standing questions about Neanderthal behavior, such as whether they could talk. Humans have two particular changes in the FOXP2 gene, which, in part, allow us to speak thousands of words. A close analysis shows that the Neanderthal had the same two genetic changes in its FOXP2 gene. So it is conceivable that the Neanderthal might have been able to vocalize in a way similar to us.
Since the Neanderthals were our closest genetic relative, they are a subject of intense interest among scientists. Some have raised the possibility of one day reconstructing the DNA of the Neanderthal and inserting it into an egg, which may one day become a living Neanderthal. Then, after thousands of years, the Neanderthal may one day walk the surface of the earth.
George Church of the Harvard Medical School even estimated that it would cost only $30 million to bring the Neanderthal back to life, and he even laid out a plan to do so. One could first divide the entire human genome into chunks, with 100,000 DNA pairs in each piece. Each one would be inserted into a bacterium and then altered genetically so the genome matched that of the Neanderthal. Each of these altered chunks of DNA would then be reassembled into the complete Neanderthal DNA. This cell would then be reprogrammed to revert to its embryonic state and then inserted into the womb of a female chimp.
However, Klein of Stanford brought up some reasonable concerns when he asked, “Are you going to put them in Harvard or in a zoo?”
All this talk of resurrecting another long-extinct species like the Neanderthal “will doubtless raise ethical worries,” cautions Dawkins. Will the Neanderthal have rights? What happens if he or she wants to mate? Who is responsible if he or she gets hurt or hurts someone else?
So if the Neanderthal can be brought back to life, can scientists eventually create a zoo for long-extinct animals, like the mammoth?
BRING BACK THE MAMMOTH?
The idea is not as crazy as it sounds. Already, scientists have been able to sequence much of the genome of the extinct Siberian mammoth. Previously, only tiny fragments of DNA had been extracted from woolly mammoths that were frozen in Siberia tens of thousands of years ago. Webb Miller and Stephan C. Schuster of Pennsylvania State University did the impossible: they extracted 3 billion base pairs of DNA from the frozen carcasses of the mammoths. Previously, the record for sequencing the DNA of an extinct species was only 13 million base pairs, less than 1 percent of the animal’s genome. (This breakthrough was made possible by a new sequencing machine, called the high-throughput sequencing device, that allows one to scan thousands of genes at once, rather than individually.) Another trick was knowing where to look for ancient DNA. Miller and Schuster found that the hair follicle of the woolly mammoth, not the body itself, contained the best DNA.
The idea of resurrecting an extinct animal may now be biologically possible. “A year ago, I would have said this was science fiction,” Schuster said. But now, with so much of the mammoth genome sequenced, this is no longer out of the question. He even sketched how this might be done. He estimated that perhaps only 400,000 changes in the DNA of an Asian elephant could create an animal that had all the essential features of a woolly mammoth. It might be possible to genetically alter the elephant’s DNA to accommodate these changes, insert this into the nucleus of an elephant egg, and then implant the egg into a female elephant.
Already, the team is looking to sequence the DNA from yet another extinct animal, the thylacine, an Australian marsupial, closely related to the Tasmanian devil, that became extinct in 1936. There is also some talk of sequencing the dodo bird. “Dead as a dodo” is a common expression, but it may become obsolete if scientists can extract usable DNA from the soft tissue and bones of carcasses of dodos that exist in Oxford and elsewhere.
JURASSIC PARK?
This naturally leads to the original question: Can we resurrect the dinosaurs? In a word, perhaps no. A Jurassic Park depends on being able to retrieve the intact DNA of a life-form that died out more than 65 million years ago, and this may be impossible. Although soft tissue has been found within the thigh bones of dinosaur fossils, so far no DNA has been extracted in this way, only proteins. Although these proteins have chemically proven the close relationship between the Tyrannosaurus rex and the frog and chicken, this is a far cry from being able to reclaim the genome of a dinosaur.
Dawkins holds out the possibility, however, of being able to genetically compare the genome of various bird species with reptiles and then mathematically reconstruct the DNA sequence of a “generalized dinosaur.” He notes that it is possible to induce chicken beaks to grow tooth buds (and induce snakes to grow legs). Hence, ancient characteristics, which have long vanished into the sands of time, might be lingering within genomes.
This is because biologists now realize that genes can be turned on and hence can also be turned off. This means that the genes for ancient characteristics may still exist but simply be dormant. By turning on these long-dormant genes, it might be possible to bring back these ancient traits.
For example, in the ancient past, chicken feet once had webbing. The gene for webbing did not disappear but was simply turned off. By turning this gene back on, one can in principle create chicken with webbed feet. Similarly, humans once were covered with fur. However, we lost our fur when we began to sweat, which is a very efficient way to regulate the temperature of the body. (Dogs don’t have sweat glands, and so cool themselves off by panting.) The gene for human fur apparently still exists but has been turned off. Thus, by turning on this gene, it might be possible to have people with fur all over their bodies. (Some have speculated that this may be responsible for the werewolf legend.)
If we assume that some of the genes of the dinosaurs were in fact turned off for millions of years but still survive in the genome of birds, then it might be possible to reactivate these long-dormant genes and induce dinosaur characteristics in birds. So Dawkins’s proposal is speculative but not out of the question.
CREATING NEW LIFE-FORMS
This raises the final question: Can we create life according to our wishes? Is it possible to create not just long-extinct animals but also animals that have never existed before? For example, could we make a pig with wings or an animal described in ancient mythology? Even by the end of this century, science will not be able to create animals to order. However, science will go a long way to being able to modify the animal kingdom.
So far, the limiting factor ha
s been our ability to move genes around. Only single genes can be reliably modified. For example, it is possible to find a gene that causes certain animals to glow in the dark. This gene can be isolated, then placed in other animals so they glow in the dark. In fact, research is currently going on whereby family pets may be modified by the addition of single genes.
But creating an entirely new animal, like a chimera from Greek mythology (which is the combination of three different animals), requires the transposition of thousands of genes. To create a pig with wings, you would have to move the hundreds of genes that represent the wing and make sure all the muscles and blood vessels match up properly. This is far beyond anything that can be done today.
However, inroads have been made that might facilitate this futuristic possibility. Biologists were amazed to find that the genes that describe the layout of the body (from head to toe) were mirrored in the order in which they appear in the chromosomes. These are called the HOX genes, and they describe how the body is constructed. Nature, apparently, has taken a shortcut, mirroring the order of the organs of the body with the sequence found in the chromosomes themselves. This, in turn, has greatly accelerated the process by which the evolutionary history of these genes can be deciphered.
Furthermore, there are master genes that apparently govern the properties of many other genes. By manipulating a handful of these master genes, you can manipulate the properties of dozens of other genes.
In retrospect, we see that Mother Nature has decided to create the layout of the body in much the way an architect might create blueprints. The geometric layout of the blueprint is in the same order as the actual physical layout of the building. Also, the blueprints are modular, so that blocks of sub-blueprints are contained in a single master blueprint.
In addition to creating entirely new hybrid animals by exploiting the modularity of the genome, there is also the possibility of applying genetics to humans, using biotechnology to bring back historical figures. Lanza believes that as long as an intact cell can be extracted from a long-dead person, it will be possible to bring this person back to life. In Westminster Abbey, we have the carefully preserved bodies of long-dead kings and queens, as well as poets, religious figures, politicians, and even scientists like Isaac Newton. One day, Lanza confided to me, it may be possible to find intact DNA within their bodies and bring them back to life.
In the movie The Boys from Brazil, the plot revolves around bringing back Hitler. One should not believe, however, that one will be able to bring back the genius or notoriety of any of these historic figures. As one biologist noted, if you bring back Hitler, maybe all you get is a second-rate artist (which is what Hitler was before he led the Nazi movement).
BAN ALL DISEASES?
The prophetic movie Things to Come was based on a novel by H. G. Wells and predicted the future of civilization, where World War II unleashed a cycle of endless suffering and misery. Eventually, all the achievements of the human race are reduced to rubble, with gangs of warlords ruling over crushed, impoverished people. But at the end of the movie, a group of farsighted scientists, armed with powerful superweapons, begin to restore order. Civilization finally rises again from the ashes. In one scene, a child is taught the brutal history of the twentieth century and learns about something called colds. What is a cold, she asks? She is told that colds were something that were cured a long time ago.
Maybe not.
Curing all diseases has been one of our most ancient goals. But even by 2100, scientists will not be able to cure all diseases, since diseases mutate faster than we can cure them, and there are too many of them. We sometimes forget that we live in an ocean of bacteria and viruses, which existed billions of years before humans walked the surface of the earth, and will exist billions of years after Homo sapiens is gone.
Many diseases originally came from animals. This is one of the prices we paid for the domestication of animals, which began roughly 10,000 years ago. So there is a vast reservoir of diseases lurking in animals that will probably outlast the human race. Normally, these diseases infect only a handful of individuals. But with the rise of large cities, these communicable diseases could spread rapidly among the human population, reaching critical mass and creating pandemics.
For example, when scientists analyzed the genetic sequence of the flu virus, they were surprised to find its origin: birds. Many birds can carry variations of the flu virus without any effects. But then pigs sometimes act as genetic mixing bowls, after eating bird droppings. And then farmers often live near both. Some speculate that this is the reason the flu virus often comes from Asia, because farmers there engage in polyfarming, i.e., living in close proximiy to both ducks and pigs.
The recent H1N1 flu epidemic is only the most recent wave of bird flu and pig flu mutations.
One problem is that humans are continually expanding into new environments, cutting down forests, building suburbs and factories, and in the process encountering ancient diseases lurking among the animals. Because the human population is continuing to expand, this means that we expect to find more surprises coming out of the forest.
For example, there is considerable genetic evidence that HIV began as simian immunodeficiency virus (SIV), which originally infected monkeys but then jumped to humans. Similarly, the hantavirus affected people in the Southwest as they encroached on the territory of prairie rodents. Lyme disease, which is spread largely by ticks, has invaded the suburbs of the Northeast because people now build houses close to the forests where the ticks live. The Ebola virus probably affected tribes of humans back in antiquity, but it was only with the coming of jet travel that it spread to a larger population and made the headlines. Even Legionnaires’ disease is probably an ancient one that spawned in stagnant water, but it was the proliferation of air-conditioning units that spread this disease to the elderly on cruise ships.
This means that there will be plenty of surprises to come, with new waves of exotic diseases dominating the headlines of the future.
Unfortunately, cures for these diseases may be late in coming.
For example, even the common cold currently has no cure. The plethora of products found in any drugstore for it treats only the symptoms, rather than killing the virus itself. The problem is that there are probably more than 300 variations of the rhinovirus that causes the common cold, and it is simply too expensive to create a vaccine for all 300.
The situation for HIV is much worse, since there may be thousands of different strains. In fact, HIV mutates so rapidly that, even if you can develop a vaccine for one variety, the virus will soon mutate. Devising a vaccine for HIV is like trying to hit a moving target.
So while we will cure many diseases in the future, probably we will always have some disease that can evade our most advanced science.
BRAVE NEW WORLD
By 2100, when we will have control over our genetic destiny, we have to compare our fate with the dystopia laid out by Aldous Huxley in his prophetic novel Brave New World, which is set in the year 2540. The book caused universal shock and dismay when it was first published in 1932.
Yet more than seventy-five years later, many of his predictions have already come to pass. He scandalized British society when he wrote about test tube babies, when recreation and procreation would be separated, and when drugs became commonplace, yet today we live in a world where in vitro fertilization and birth control pills are taken for granted. (The only major prediction he made that has not come to pass is human cloning.) He envisioned a hierarchical world where doctors deliberately clone brain-damaged human embryos, which grow up to become servants of the ruling elite. Depending on the level of mental damage, they could be ranked into the Alphas, who are perfect and destined to rule, down to the Epsilons, who are little more than mentally retarded slaves. So technology, instead of liberating humanity from poverty, ignorance, and disease, has become a nightmare, enforcing an artificial and corrupt stability at the expense of enslaving an entire population.
Althou
gh the novel was accurate in many ways, Huxley did not anticipate genetic engineering. If he had known about this technology, then he might have worried about another problem: Will the human species split into fragments, with fickle parents and devious governments meddling with the genes of our children? Parents already dress their kids in outlandish outfits and make them compete in silly contests, so why not change the genes to fit the parents’ whims? Indeed, parents are probably hardwired by evolution to give every benefit to their progeny, so why not tamper with their genes as well?
As an elementary example of what might go wrong, consider the lowly sonogram. Although doctors innocently introduced the sonogram to help with pregnancies, this has led to a massive epidemic of abortions of female fetuses, especially in the countrysides of China and India. One study in Bombay found that 7,997 out of 8,000 aborted fetuses were female. In South Korea 65 percent of all third-born children are male. The generation of children whose parents chose this gender-based abortion will soon be of marriageable age, and millions will find that there are no females to be found. This in turn could cause enormous social dislocation. Peasants who wanted only boys to carry on their name will find that they have no grandchildren.