As scientists discover more of the genes that make the human brain the biggest and smartest on Earth, they also are handing the human race the keys for upgrading the organ of intelligence to daring new heights, possibly even super-IQ babies.
But they are also the keys to a Pandora’s box filled with an unprecedented assortment of potentially good and bad things, some things likely to shake the foundations of cherished beliefs and hopefully something good.
Among the sticky questions: Do great apes, our nearest genetic relatives, deserve some sort of secondary citizenship?
Although humans have much bigger and more complex brains than non-human primates, the brains of the apes are the closest to us and they may share some of the same thought processes that are believed to be unique to humans.
The human brain went through an explosive period of growth millions of years ago, and at least 17 of the genes that caused the accelerated expansion were discovered by Bruce Lahn and his colleagues at the University of Chicago.
As these genes fall into our hands, society will be faced with ethical and moral questions that will dwarf the controversy over human cloning.
“It’s where the most challenging social questions will arise of the `Do we want to go there?’ type,” said Maynard Olson, professor of medicine and genome sciences at the University of Washington.
Is there some knowledge that’s too dangerous to pursue? Or should we seek out all knowledge but limit its use?
“We just no longer control this discussion, if we ever did,” Olson said. “Science is global, knowledge is global, values are not global. People will certainly try. In the end it’s going to be what people think that’s going to determine where humans go.”
Genes for intelligence or creativity can, for instance, be used to select embryos possessing the most favorable ones, a choice that may be just around the corner.
Or they can be used to genetically engineer supersmart children, or dogs or cats, for that matter, a possibility that, admittedly, is still far off.
“I have no doubt that humans are someday going to muck around with their own genes, even by introducing new genes, but it’s going to take a while,” Lahn said.
Placing the genes that operate the brain under the microscope also may give scientists and philosophers an opportunity to learn more about whether we operate by free will or if our actions are biologically determined, or, as is most likely the case, our behavior is the result of both nature and nurture.
And regardless of how humans decide to use science to alter their brains, people will naturally become smarter as a result of evolutionary pressures that favor the survival of the smartest brain genes.
“There’s no reason that the evolution of these genes … stopped after modern humans emerged,” Lahn said. “These genes are still evolving in the sense that within human populations there are still mutations that are arising that make some people a little smarter than others.”
Can we resist the temptation to manipulate these genes to speed up the slow evolutionary movement toward a better brain?
Experts argue over the pros and cons. Some insist it can’t be done because there are too many scientific unknowns. Some say it shouldn’t be done even if it’s possible.
“My concern is whether people are foolish enough to think that they can manipulate the human genome successfully. That’s asking for trouble,” said Dr. Ajit Varki, a physician scientist at the University of California-San Diego, who is helping decode the chimpanzee genome.
“We barely know the absolute minimum of how these work,” he said. “The amount of trouble that messing around with it could cause is much more than any benefit we might gain.”
But others see it differently, saying it is our future that would benefit if we do it wisely.
“Why not make it so that people could write more wonderful symphonies, or think up answers to cancer therapies or just be kinder to one another. That’s why it’s tempting,” said Laurie Zoloth, professor of medical humanities, bioethics and religion at Northwestern University’s Feinberg School of Medicine.
“I think it could be done and I hope it will be done, but I hope it’s done with exquisite care and exquisite attention to the ethical issues,” she said. “I also hope that if it is a great good it is more fully shared than so many of the benefits of modernity have been shared.”
Humans have long used breeding to induce genetic changes in animals and plants to dramatically alter their behavior, appearance or nutritional content.
Domesticating the wolf, for example, probably started 100,000 years ago and led to the first recognizable dog about 14,000 years ago. Today there’s a spectacular variety of dog breeds, ranging from the Great Dane to the Chihuahua and possessing a wide variety of smarts.
But domestication can be accomplished far more rapidly. Even though the silver fox is raised for its prized furs, it has never been tamed, biting and fighting whenever it gets a chance.
By carefully selecting puppies that exhibited the least wild behavior and only allowing them to breed, and then selecting for further breeding the less aggressive pups in succeeding generations, Russian geneticists began producing tame foxes after 20 generations. They acted like dogs, wagging their tails and wanting to be petted.
“Before our eyes, `the Beast’ has turned into `Beauty,’ as the aggressive behavior of our herd’s wild progenitors entirely disappeared,” wrote Lyudmila N. Trut of the Russian Academy of Sciences.
Breeding changes many genes as it pushes forward those genes desired by breeders, such as a milder temperament. While many genes may be involved in a trait, changes in only a few may drastically alter the trait. That’s why breeders could quickly select for pointing, hunting, retrieving, guarding, herding or swimming.
Scientists now are narrowing their search and focusing on finding specific genes for behavior. What is it that makes humans and animals friendly or aggressive, cuddly or cold, monogamous or promiscuous, a homebody or an adventurer?
Some answers are beginning to come in. Genetic studies of a little rodent called the vole show why some male animals are cads while others are loving mates.
The prairie vole sticks by its mate while the meadow vole is faithless. Researchers found that the prairie vole makes more of a neurotransmitter called vasopressin than its meadow cousin. When scientists upgraded the gene for vasopressin production in the meadow vole, it too became monogamous.
Humans and animals share many of the same genes, such as for vasopressin. Another gene, which makes oxytocin, was found to be important for recognizing another individual, and the forager gene determines whether a bee will go out and explore or remain in the hive.
Scientists found that when they manipulate these genes they also manipulate behaviors, making a mouse more sociable, for instance, or getting a housekeeping bee to venture out of the hive and explore the outside world. That genes influence our behavior is clear. The question is to what degree? And what role does culture play in influencing the behavior of genes?
“I teach my students that behavior is willed. That ethics are conscious. That friendship and altruism are moral gestures,” Zoloth said. “And it’s disconcerting to think, well, wait a minute, what if those are actually genetic substrates working themselves out in different people?”
Lahn’s studies at the University of Chicago show that a fortuitous series of genetic mutations made the human brain special. Animals are born with instincts. They can eat, run and swim right away. Humans can’t. They are born to learn, making them far more adaptable to almost any environment they venture into.
“Humans evolved their cognitive abilities not due to a few accidental mutations, but rather, from an enormous number of mutations acquired through exceptionally intense selection favoring more complex abilities,” Lahn said.
The big brain, in a sense, shifted evolution from the survival of the fittest to the survival of the brightest, enabling early humans to advance from an endangered species category to No. 1. The brains of the great apes–gorilla, chimpanzee, bonobo and orangutan–benefited from some of this genetic exuberance, but to a far lesser degree.
Nevertheless, their cognitive skills are impressive. They can recognize themselves in a mirror. Their social and cultural activities are more complex than those of other animals. Some can use rudimentary tools.
“Every time we try to say we have a property the other animals don’t–tool using, language, consciousness, the ability to follow directions–we find something, a crow, parrot, monkey, bee or dolphin that’s able to do it too,” said Arthur Caplan, director of the University of Pennsylvania’s Center for Bioethics.
“What makes us unique is that we have this giant thing inside our heads that is capable of doing many different sorts of mental, computational, emotional and cognitive functions, no one of which makes us special, but all together puts us in a different category,” he said.
Great apes have many cognitive abilities that are humanlike, said Varki. “They are deserving of some different kind of attention. They’re not humans. They should not be treated like humans. But they need to be treated considerably differently than other animals.”
Lahn’s discovery of some of the genes that make the human brain so much better than that of the great apes provides a tool for changing the brain that was not available before.
The first use may be in preimplantation selection, in which a fertilized egg is examined to see whether it might have genes for, say, higher IQ. Preimplantation selection is already in use, having been developed to prevent an egg carrying a genetic disease from being implanted into a woman’s uterus.
“We’ve already got a path for doing this,” said the University of Washington’s Olson. “You name the trait, pick the smartest embryo to implant, and you’ve got a new kind of eugenics, eugenics for the rich.”
The scenario that raises the greatest concern is the possibility of making apes and other animals smarter by genetically engineering them with human brain genes. Their brains can then be studied for new clues to Alzheimer’s disease, Parkinson’s and other brain disorders.
Putting human brain genes in animals could also help scientists learn more about the great mystery of consciousness.
But what about the animals? Will a more sentient brain give an ape human-like consciousness trapped in an animal body? Or would you have a thoughtful, clever and linguistically able primate?
“You’d have to do some serious thinking about the harm that would be done if you went in this direction,” said Northwestern’s Zoloth. “It’s harmful to do meaningless research that doesn’t have an immediate health benefit. You need a very strong reason for creating a more sentient brain in a nonhuman primate.”
