It is possible that the key to the mysteries of intelligence lies in the study of our ape-like ancestors. Then another question arises: can such a study bring to life the plot of “Planet of the Apes”? In this series of films, shot over a long period of time, the plot is based on the fact that a nuclear war destroys modern civilization. Humanity is plunging into barbarism, but radiation somehow accelerates the evolution of other primates, which become the dominant species on the planet. They create an advanced civilization, while people who have turned into shaggy, foul-smelling savages wander half-naked through forests or, at best, end up in zoos. Humans and primates have switched places, and now great apes are staring at us from behind the bars. In the recent film Rise of the Planet of the Apes, scientists are searching for a cure for Alzheimer’s disease and along the way stumble upon a virus, the unexpected side effect of which is to increase the intelligence of chimpanzees. Unfortunately, one of these wiser chimpanzees is unlucky: he ends up in a primate shelter and is subjected to abuse there. Using his newfound abilities, the chimpanzee breaks free and infects other laboratory animals with the same virus to increase their intelligence; after that, he releases all the animals from their cages. Soon, a whole caravan of screaming intelligent monkeys appears on the Golden Gate Bridge, causing real chaos and stunning the local police. There is a bloody fight with the police. The film ends with the primates finding refuge in a nature reserve that becomes their home. Is such a scenario realistic? Not in the short term, but it is impossible to rule out such a development in the future, since very soon scientists will be able to catalog all the genetic changes that led to the emergence of the species Homo sapiens. But before the appearance of intelligent primates, it will still be necessary to find answers to many mysteries. Among the scientists who are passionate not about science fiction, but about the question of what makes us human, we can name Dr. Catherine Pollard, a specialist in bioinformatics, a discipline that arose very recently and practically did not exist even ten years ago. In this field of biology, scientists, instead of cutting up animals and figuring out how they work, use the enormous capabilities of computer technology to mathematically analyze animal genes. Dr. Pollard is at the forefront of those who are looking for genes that distinguish us from great apes. She received a serious chance of success back in 2003, having just defended her dissertation. “I was thrilled to be able to join an international team working to determine the sequence of DNA bases, or “letters,” in the genome of an ordinary chimpanzee,” she recalls. She had a very definite, clear goal. She knew that only the 15 million base pairs, or “letters,” that make up our genome (out of 3 billion base pairs) distinguish us from chimpanzees, our closest genetic relatives. (Each “letter” of our genetic code stands for a nucleic acid, of which there are four types – A, T, C, and G. So our genome consists of 3 billion letters in a certain order: ATTCCAGGG..) “I decided to find them all,” she writes. Isolating these genes would be of great importance for our future. Knowing which genes define Homo sapiens, we could determine how human evolution went. Probably, the secret of the mind lies in these genes. It is even possible that with their help it is possible to accelerate the evolutionary path and even increase intelligence. But 15 million base pairs is a huge number, and analyzing them will take a long time. How do you find a handful of genetic needles in this genetic haystack? Dr. Pollard knew that most of our genome is made up of “junk” DNA, which does not contain any genes and is practically untouched by evolution. This junk DNA slowly mutates with a known frequency (approximately 1% changes over 4 million years). Since it is known that our DNA differs from that of chimpanzees by 1.5%, we can conclude that we and chimpanzees diverged in our development about 6 million years ago. Therefore, there is a “molecular clock” in each of our cells. And since evolution increases the rate of mutation, analyzing the point where the acceleration occurred allows us to tell which genes served as the engines of evolution. Dr. Pollard decided that if she could write a computer program that would determine where most of these accelerated changes were concentrated in the genome, then it would be possible to isolate those genes that gave rise to the species Homo sapiens. After a few months of work, she finally introduced her program into the giant computers that the University of California at Santa Cruz has, and began to look forward to the results. When the printout appeared, it had all the necessary information on it. There are 201 regions in our genome that show accelerated changes. But the first entry on the list caught her attention. “Together with my mentor David Haussler, who was looking over my shoulder, I looked at the very first entry – 118 bases, which collectively became known as HAR1 (Human Accelerated Region),” recalls Dr. Pollard. She was overjoyed. Eureka! “We were lucky to break the bank,” she later wrote. A dream come true. In front of her was a section of the genome that included only 118 bases, with the maximum concentration of mutations that distinguish us from great apes. Of these base pairs, only 18 mutations have changed since we became humans. Dr. Pollard’s remarkable discovery has shown that perhaps a tiny handful of mutations are responsible for humanity’s rise from the quagmire of the genetic past. Next, Dr. Pollard and her colleagues tried to decipher the exact nature of this mysterious cluster, HAR1. It turned out that for millions of years, HAR1 remained surprisingly stable. Primates diverged from chickens about 300 million years ago, but there are only two base pairs that distinguish them in the HAR1 region. It can be said that the HAR1 region has hardly changed for several hundred million years (only two letters have changed – G and C). And in just 6 million years, 18 mutations occurred in HAR1 – a gigantic acceleration of evolution. Even more mysterious was the role that HAR1 plays in controlling the general location of the cerebral cortex, famous for its convolutions. A defect in the HAR1 region causes a disorder known as lissencephaly, or smooth brain; in this disease, the cerebral cortex does not stack properly. (In addition, defects in this area are associated with schizophrenia.) The cortex of our brain is not only significantly large; one of its main characteristics is its strong wrinkling and tortuosity, which greatly increases the surface area of the cortex and, consequently, its computational abilities. Dr. Pollard’s work has shown that changing just 18 letters of our genome is partly responsible for this, one of the most serious and defining genetic changes in human history, which greatly enhanced our intelligence. (Let us recall, by the way, that the brain of Karl Friedrich Gauss, one of the greatest mathematicians in history, was preserved after his death and turned out to be particularly wrinkled.) Dr. Pollard’s list was not limited to this: several hundred more sites were identified where accelerated changes were observed, and some of these sites were known before. FOX2, for example, is fundamentally important for speech development, another key human trait. (People with the defective FOX2 gene have difficulty moving the facial muscles necessary for articulate speech.) Another area, known as HAR2, gives our fingers the flexibility and dexterity needed to use delicate tools. Moreover, not so long ago it was possible to sequence the Neanderthal genome, so we can compare our genetic apparatus with that of a species even closer to us than the chimpanzee. (Analysis of the FOX2 gene has shown that this gene is identical between us and Neanderthals. So it’s quite possible that Neanderthals, like us, could use speech.) Another very important gene has been named ASMP; it is believed that it is responsible for the explosive growth of our brain’s capabilities. Some scientists believe that this and other genes may tell us why humans have become intelligent, but higher primates have not. (People with a defective ASMP variant often suffer from microcephaly, a severe form of mental retardation, because they have a very small skull, about the same as that of Australopithecus, one of our ancestors.) Scientists tracked the ASPM gene mutations and found out that over the past 5-6 million years (since our paths parted with chimpanzees), it has mutated about 15 times. The most recent mutations of this gene seem to correspond to important milestones in our evolution. For example, one such mutation occurred more than 100,000 years ago, when a modern human appeared in Africa, outwardly indistinguishable from us. And the last mutation took place 5,800 years ago, which coincides with the advent of writing and agriculture. Since these mutations coincide with periods of rapid intelligence growth, there is a strong temptation to conclude that ASPM belongs to the handful of genes responsible for intelligence. If this is true, then it may well be possible to determine whether these genes are active today and whether they will continue to determine human evolution. All this data raises the question: is it possible to increase intelligence by manipulating a handful of genes? It is quite possible. Scientists are on the verge of pinpointing the mechanism by which these genes contributed to the growth of intelligence. In particular, genetic regions and genes such as HAR1 and ASPM could help us solve the mystery of the brain. If there are approximately 23,000 genes in the human genome, then how can these genes control the connections between a billion neurons (after all, there are about a quadrillion – a unit with fifteen zeros – connections)? From a purely mathematical point of view, this seems impossible. The human genome is about a trillion times smaller than it needs to encode all neural connections. So mathematically, our existence seems impossible. But perhaps the answer is that nature uses numerous tricks to create a brain. Firstly, many neurons are connected randomly, so a detailed plan is simply not needed; and this means that randomly connected areas organize themselves after the birth of a child and begin to interact with the outside world themselves. Secondly, nature, among other things, uses modules that are repeated over and over again. Having stumbled upon something useful once, she often repeats this discovery later. Perhaps that is why only a handful of genetic changes are responsible for most of the explosive growth of our intelligence over the past 6 million years. Therefore, size matters in this case. If we slightly tweak ASPM and some other genes, our brain can become bigger and more complex, and, consequently, there will be an opportunity for the development of intelligence. (Simply increasing the size of the brain is not enough, because it is fundamentally important how this brain is organized. But increasing the volume of gray matter is a necessary prerequisite for improving intelligence.) M. Kaku “The Future of reason” Picture: www.thedigitaltransformationpeople.com