Speech gene. Language gene

Despite the variety of tricks that laboratory mice can perform, scientists are still trying to expand the arsenal of tricks of their charges. Super-endurance, super-strong, super-fast, super-resistant or, conversely, super-susceptible to the most dangerous diseases - the list of abilities genetically acquired at the will of scientists is not limited to this.

Wolfgang Enard from the Max Planck Institute for Evolutionary Anthropology in Leipzig and his colleagues have set themselves the almost impossible task of teaching mice to speak.

Well, or at least transplant the human version of the Foxp2 speech gene into mice.

Mice, and other animals, including primates, also have this gene, or more precisely, the DNA sequence encoding the transcription factor Foxp2, but differs from humans by two point mutations. It is believed that it was these mutations that gave humans the unique ability to both speak and distinguish speech. Scientists differ in estimates of the age of this mutation - from 100 to 500 thousand years. The question of the age and evolution of Foxp2 even became almost the main topic in the discussion of the recently deciphered genome of Neanderthals.

However, the effects of this transcription factor remain unclear. It is obvious that such a complex process as speech cannot be ensured by just one gene; an appropriate structure of the respiratory tract and vocal cords is necessary. In addition, the brain and hearing organ must be able to perceive and distinguish this very speech. Foxp2 is perfectly suited to the role of a “regulator” - after all, it is a transcription factor that regulates the work of a wide variety of genes (which ones are not fully known). That is, one mutation in the Foxp2 gene is enough to change the structure, properties and functions simultaneously in several tissues - be it the nervous or respiratory system.

Foxp2 became a “speech gene” relatively recently: at the end of the last century, it became clear that its mutations are the cause of congenital speech perception defects.

But the mechanism of action, as well as all the functions of this factor, remained unknown until today. Looking ahead, let's say that even after Enard's work many questions remained, although scientists were able to describe the effects of the human version of Foxp2 on mice. The authors of the publication in Cell, whose listing along with their institutes took up the entire first page of the article, tried to answer two questions at once: what is the role of Foxp2 in general and what is the difference between the effects of human Foxp2 and mouse Foxp2.

To do this, they first had to breed mice heterozygous for this gene - Foxp2wt/ko (wild type/knockout), that is, one version of this gene was “wild” - mouse, and the second was completely turned off. In addition to this group, the scientists also obtained Foxp2hum/hum (human) mice, which had the human variant of the gene in both positions. After which Enard and his colleagues, among whom was the “chief expert” on the Neanderthal genome, Svante Peebo, assessed the mice according to almost three hundred physiological criteria.

The “humanized” mice never learned to speak and even had less dopamine secretion and diminished research enthusiasm, but they emitted quantitatively different ultrasounds.

The absence of one copy of the gene led to a completely opposite effect, which once again proves the role of the human version of Foxp2 in all observed phenomena. The reason for these differences is in the basal ganglia of the telencephalon. It is here that signals are redirected from the cerebral cortex to the muscles, and many reflexes are “closed” here. The decrease in activity in searching and exploring new objects is explained by low levels of dopamine, a pleasure mediator that stimulates such behavior.

As for the main topic of discussion - the effect on speech, most of the differences turned out to be insignificant, although the authors were able to find a small difference:

“humanized” mice tended to produce more individual sounds and used lower peak frequencies to do so compared to knockout mice for one of the genes.

However, this only demonstrates the role of a specific human version, and not Foxp2 as a whole.

Foxp2 appears to have the greatest impact on speech and sound recognition, as well as central speech regulation. The most interesting thing the mice, who never learned to speak during their lifetime, told scientists after dissection:

In “humanized” mice, the average length of short processes of nerve cells - dendrites - was 22% greater.

This contributes to the formation of more contacts between cells, and consequently, more efficient functioning of the nervous system and, in particular, the auditory analyzer.

Thus, Enard once again confirmed the fact that evolution within such a perfect group as animals proceeded mainly due to transcription factors, and not genes in the usual sense of the word. It remains to look for Foxp2 in parrots, and the question of its role will be finally resolved.

Comparing entire genomes from different species has provided insight into why humans and chimpanzees are so different from each other despite the great similarity of their genomes. In recent years, the genomes of thousands of species (mostly microorganisms) have been sequenced. It turned out that what matters most is in which part of the genome the changes occur, and not in their total number. In other words, you don't need to change the genome much to create a new species. In order for our common ancestor with chimpanzees to develop into humans, there was no need to speed up the molecular clock as a whole. The secret was to quickly make changes in places where they would have a significant impact on the functioning of the entire body. Such an example, along with the HAR1 sequence, is the rapidly changing sequence contained in the FOXP2 gene.

It is known to be associated with speech: in 2001, it was shown that people carrying mutations in this gene are unable to make some of the rapid facial muscle movements needed to articulate words, despite having normal cognitive language abilities. Normally, this sequence has several differences from the similar one in chimpanzees: two nucleotide substitutions that changed its protein product, and many other substitutions that apparently affected how, when and where the protein is used in the human body.

A recent discovery sheds some light on the question of when hominids evolved a speech-producing version of FOXP2. In 2007, scientists at the Max Planck Institute for Evolutionary Anthropology in Leipzig sequenced FOXP2, extracted from the remains of Neanderthals, and found that these extinct humans possessed the modern human version of the gene. It is likely that they could talk the same way as we do. The latest estimates of the time of separation of the evolutionary lineages of Neanderthals and modern humans indicate that the new form of FOXP2 appeared no later than half a million years ago. However, most of the features that distinguish human speech from sound communication in other animals are due not to physical characteristics, but

The speech gene helps to move from one stage of learning, at which understanding and comprehension of the task occurs, to another, when the desired skill is learned to an automatic state.

Speech abilities are ensured by the work of a special neural apparatus, and the structure of neural networks depends on genes, so it would be absolutely correct to assume that we have special “speech genes”. However, until 2001, scientists knew almost nothing about which genes influence speech. The situation changed after a study of one family, whose members suffered from speech defects, and they had problems not only with pronunciation, but also with syntax and with understanding other people's speech. It turned out that the gene was mutated in this family FOXP2, who instantly became a “star” in the scientific world.

Our ability to speak is due to several mutations in the speech gene. (Photo by H. ARMSTRONG ROBERTS/Corbis).

Striatum in the human brain. (Photo Wikipedia).

It soon became clear that he is responsible not only for the intelligibility of speech: apparently, man generally learned to speak with the help of FOXP2. It was, of course, also found in chimpanzees, but in them it differed from humans in two nucleotide “letters” in the DNA; mutations probably helped transform animal sounds into complex speech. In 2009, a curious experiment was performed: human FOXP2 were introduced into the genome of mice, after which the latter, of course, did not begin to speak in a human voice, but the sounds they made became noticeably more complex. Further studies showed that in mice with the human speech gene, the activity of neurons in the striatum (or striatum), which, among other things, is involved in learning processes, changed. Moreover, even the notorious female talkativeness was linked to this gene - after it turned out that the protein level FOXP2 in girls it is almost a third higher than in boys. However, the details of how this gene helps us learn speech remained largely unclear.

In us and in animals, learning occurs in two stages. At the first stage, the task is divided into several steps, which we gradually learn to perform. In the case of, for example, riding a bicycle, we take the steering wheel in our hands (and try to keep it level), then we put our feet on the pedals, and then we begin to rotate them. At first, this sequence of actions requires our full concentration, but over time the “unconscious” part of the learning begins, when we learn to ride better and better, simply by repeating all the above actions. The same thing happens with learning a language: first we concentrate on the pronunciation and meaning of individual words, then speech becomes increasingly fluent, and, in the end, we can say “good afternoon” automatically, without thinking about how and what we we talk.

Researchers from (USA) decided to find out which stage of learning requires a speech gene FOXP2. In the experiment, normal mice and mice with the human gene had to find a maze to get a treat. The “humanized” animals were quicker to understand which route would be the fastest to get to food, but when the maze was designed so that the learning stages could be separated and observed separately from each other, there was no difference between the mice.

Then the hypothesis arose that the speech gene helps switch between different phases of learning. Further experiments, described in an article in the Proceedings of the National Academy of Sciences, confirmed this assumption: mice that had mastered the step-by-step phase of the task switched more quickly to the repetition learning phase if human FOXP2 was introduced into their genome. The effect was also seen at the cellular level: in the striatum, different zones are responsible for different stages of learning, and the one that was responsible for learning through repetition was activated more effectively in mice with the human gene.

That is, we can say that the human version of the gene FOXP2(which is believed to have arisen about 200 thousand years ago) opened up learning by repetition to our ancestors - a person could not only pronounce a word and understand its meaning, but the reproduction of this word became automatic. The increased ability to communicate as a group helped individuals survive, so the new version of the gene gained an evolutionary advantage. However, it is unlikely that the development of speech in humans occurred “at the will” of just one gene. Obviously, there is a whole genetic network involved, in which FOXP2- just one of the links. So, a year ago, researchers from Johns Hopkins University School of Medicine (USA) published an article in which they described a drug-dependent FOXP2 gene SRPX2, which controls the dynamics of interneuron connections in the speech center of the brain. It is also worth noting that in the described experiments with the gene FOXP2 the ability of mice to learn in general was assessed, so it is likely that this gene in humans may be related not only to speech abilities.

Article for the “bio/mol/text” competition: Speech is considered a unique trait found only in humans, but other species also have their own forms of communication that are based on mechanisms similar to those of humans. The similarity is largely determined by the proximity of their genetic bases. The hero of this story is the gene FOXP2- called the “speech gene,” but it was in humans that it acquired such properties that allowed us to become who we are.

"Bio/mol/text"-2015

The sponsor of the nomination “Best article on the mechanisms of aging and longevity” is the Science for Life Extension Foundation. The audience award was sponsored by Helicon.

Sponsors of the competition: laboratory of biotechnological research 3D Bioprinting Solutions and studio of scientific graphics, animation and modeling Visual Science.

In the late 1980s, teachers at a school in west London noticed that seven children who had speech problems were growing up in the same family. This family (in the scientific literature it appears under the name “KE family”) was of Pakistani origin, and a closer study of its members revealed that in three generations of this family there are people with speech problems (Fig. 1). They had difficulty pronouncing words, and sometimes words were replaced by words that sounded similar. If they spoke Russian, then, for example, instead of the word “oven” they would pronounce “flow”. Mild, mild disorders and more severe forms of speech disorders that seriously impede communication were discovered in the family.

Figure 1. Family tree of the KE family. In three generations of the family, people were found to have speech problems of varying severity (black filled figures). These were representatives of both sexes: men (squares) and women (circles).

Given that speech problems were passed down from generation to generation, doctors who studied the KE family suggested that some kind of genetic disorder underlies these disorders. Difficulties with speech occurred in representatives of both sexes, which means that the “culprit” gene was not located on the sex chromosomes (X or Y), but on autosomes. As a result, a team of geneticists from Oxford was able to determine that the desired gene is located on chromosome 7. The KE family was also studied by linguists - for example, Mirna Gopnik ( Myrna Gopnik) from Canada. They suggested that speech disorders in the family are caused by a mutation in the “grammatical gene,” which is responsible for syntactically and grammatically correct construction of phrases. It was later found that representatives of the family under study had problems not only with syntax and articulation, but also generally experienced difficulties in controlling the tongue and lips. This disorder was later named verbal dyspraxia. The KE family's brains were unable to accurately control their lips and tongue, resulting in words not being pronounced correctly ( cm. box).

How speech occurs in the brain

For the formation of normal speech, the coordinated work of two areas of the cerebral cortex is important - Broca's area in the frontal cortex and Wernicke's zones in the temporal lobe. Broca's area is responsible for the pronunciation of words and the motor component of speech. When this area of the brain is damaged, for example due to a stroke, the patient experiences motor aphasia- inability to pronounce words or a pronounced limitation in the number of words spoken. If the pathological process affects Wernicke's area, this leads to sensory aphasia (Wernicke's aphasia) - impaired understanding of speech. A patient with severe sensory aphasia does not understand what other people say to him: instead of words, he hears an unclear set of sounds. Representatives of the KE family had problems with the functioning of the frontal cortex, that is, their speech disorders were a variant of motor aphasia.

The gene, which Oxford scientists localized on chromosome 7, was subsequently named FOXP2 (Forkhead box protein P2). It is active in the brain, as well as in the lungs and intestines. FOXP2 is one of many regulatory genes belonging to the family FOX-genes. Based on the gene, a transcription factor is synthesized, which is not directly involved in biochemical processes, but can interact with tens and hundreds of promoter regions of other genes and regulate their activity. Changing this gene leads to the fact that all the genes that “subordinate” to it will not do their job correctly.

What does FOXP2 gene say?

All FOX-genes regulate the normal development of the embryo, and FOXP2- not an exception. The expression of this gene is increased in the precursor cells of brain neurons, and when turned off FOXP2 their occurrence is suppressed. One of the ways that FOXP2 regulates cell maturation, is its control over gene activity SRPX2 (sushi repeat-containing protein X-linked 2), encoding the structure of the protein peroxiredoxin. Through this gene FOXP2 controls the formation of synapses (synaptogenesis), and reduced activity SRPX2 leads to disruption of synaptogenesis and auditory communication in mice.

During the evolutionary process, DNA can change randomly, that is, mutations occur in the molecule. Substitutions in the nucleotide sequence in which the structure of the protein does not change are called synonymous. If a replacement in DNA leads to the appearance of a new amino acid in a protein, then such a replacement is considered nonsynonymous and, as a rule, leads to changes in protein function. When studying molecular evolution FOXP2 Interesting circumstances were revealed. This gene is one of the most conserved in human DNA, and the greatest changes in FOXP2 within the group of primates occurred after the divergence of the evolutionary lines of humans and chimpanzees - our closest relatives. Rhesus macaques, gorillas and chimpanzees had only synonymous DNA substitutions, and only orangutans had one non-synonymous substitution (Fig. 2). The highly conserved structure of the gene is associated with the many functions that it regulates and their importance for the developing organism. If during mutation FOXP2 forms of the protein encoded by it arose that did not fully perform the necessary functions, which led to improper development of the embryo and its death. Such mutations could not be passed on to the next generation. Two nonsynonymous substitutions that arose in humans in the gene FOXP2, apparently, gave our ancestors a serious advantage and became entrenched in the genome Homo sapiens.

Figure 2. Gene evolution FOXP2. The numbers indicated through the line represent the number of substitutions (mutations) in the DNA sequence: the number of non-synonymous substitutions is given before the line, and synonymous ones after the line. In humans, for example, in comparison with chimpanzees, only two substitutions occurred, but both were nonsynonymous, that is, they led to a qualitative change in the gene. At the same time, 131 synonymous substitutions and only one nonsynonymous substitution occurred in mice.

Bird trills

If a person has a gene FOXP2 associated with speech, then in other animals it should regulate similar functions. The first thing that comes to mind is the singing of birds. You may think that birds always sing the same way, but this is not true. Singing is one of the tools for attracting the attention of representatives of their species. Singing in the presence of females is called directed, and when males sing “for the soul” or for the purpose of training, then such singing is considered undirected. Behind the light and airy trills of songbirds is the clear and well-coordinated work of their nervous system and the machinery of genes that control its functioning.

A model organism for studying the genetic basis of bird song is the zebra finch ( Taeniopygia guttata) (Fig. 3), and the most studied (in relation to singing) part of the bird brain is area X (area X), located in the striatum - striatum. Birds whose song changes seasonally show changes in area X throughout the year. It increases during the breeding season, when the bird needs to win a mate, and becomes smaller when this period of time ends. The increase in area X in birds is directly related to the formation of new synapses for the acquisition of new singing techniques.

Figure 4. Expression FoxP2. When directed (directed) singing, the level of gene expression is higher than in non-directed (undirected). This connection may indicate that more harmonious singing requires coordinated activity of the nervous system, which is ensured by FoxP2.

The zebra finch is not a bird whose song changes with the seasons; it is more characterized by a combination of directed and non-directed singing throughout the year. To study activity FoxP2 Not during brain development, but during different types of brain activity, scientists conducted the following experiment. Several male zebra finch sang “for the soul”, in the absence of females and males of their species, and other males sang to females, which were constantly replaced by experimenters. There was also a control group of birds that did not sing. During the experiment, an audio recording of bird songs was carried out. It turned out that during non-directional singing the level of expression FoxP2 decreases, but when directed it remains high (Fig. 4). However, with undirected singing, a greater variety of melodies was noted than with directed singing. This difference can be explained by the level of expression FoxP2: The more intense the expression, the more orderly and stable the bird's songs become. It is worth noting that the scientists who conducted the study did not indicate the reason why the finches that did not sing had expression levels FoxP2 remained high.

Another study on zebra finches clarified the role FoxP2 in the formation of singing abilities. It was determined that there are two populations of neurons in area X. The first population consists of neurons with high activity FoxP2, the second - from low. As the bird matures, the number of neurons from the first population decreases (Fig. 5), and along with it the diversity of bird songs decreases. However, the expression level FoxP2 still increases with directional singing, which indicates a biphasic influence of this gene. During adulthood, neurons in which it is actively expressed FoxP2, are responsible for the final formation of region X. After reaching functional maturity, an increase in gene activity occurs during directed singing, which requires coherence and clarity. If expression is disrupted FoxP2 in area X, then when learning to sing, birds reproduce melodies with errors and not in full. If the functioning of the “speech gene” is disrupted, the normal variability of singing motives in young and adult birds is also disrupted. This occurs due to disruption of dopaminergic modulation of area X activity. FoxP2 participates in the formation of dopamine receptors on the dendrites of area X neurons and the signal transmission system from them into the cell, which means that changes in its expression lead to problems in this circuit. The similarities between the genetic mechanisms of the formation of bird songs and human speech are described in more detail in Elena Naimark’s article on “Elements”.

Figure 5. Age-related differences in the number of neurons belonging to different populations in zebra finches. A population of neurons actively expressing FoxP2, gradually decreases as you grow older. The size of the population of “low-active” neurons is in no way related to the age of the bird.

Big-headed Mickey Mouse

Modern methods of molecular biology make it possible to “transplant” genes from one organism to another. You can introduce human FOXP2 into the genome of another animal to understand what advantages this gene variant provides in brain function.

The very first work in this direction was carried out in 2009. The object of the scientists' research was mice, in whose genome there is a “mouse” variant Foxp2 replaced by “humanized”. It should be clarified that it was not the whole gene that changed, but only two nucleotides that determine the difference in the amino acid sequences of the human and chimpanzee FOXP2 protein (the mouse protein differs in one more amino acid). All mice with the "human" gene ( hum) survived and were able to leave offspring. The study compared another type of mouse ( wt/ko), who have one of the alleles of the gene Foxp2 belonged to an ordinary mouse ( wild type, wt), and the other was a gene variant found in people with speech disorders ( ko). “Ordinary” mice were also studied, and their results were taken as a conditional norm, but were not taken into account in the discussion.

Figure 6. Dopamine levels in the brains of two groups of mice. In hum mice, compared to wt/ko mice, less dopamine is produced in different brain structures.

“Humanized” mice showed less exploratory activity than wt/ko mice, but at the same time they more often participated in group contacts. In hum mice, compared to the wt/ko group, the level of dopamine, the main “motivating” neurotransmitter, was lower in the brain (Fig. 6). There may be a direct link between dopamine levels and exploratory behavior. The reduced level of dopamine in hum mice does not create motivation to act as strongly and in such quantities as in wt/ko mice. However, this is not to say that this is bad. In a sense, hum mice can be said to be less fussy and more focused than their wt/ko counterparts. In the striatum (an area rich in dopamine neurons) of hum mice, neurons with longer dendrites were found - processes that transmit information to other cells. Besides this, the normal human variant Foxp2 increased neuroplasticity in the brain of hum mice. In general, it seems that the “humanization” of the gene streamlined the functioning of the nervous system of hum mice due to finer tuning of dopaminergic signal transmission.

Another study, conducted by a group of European scientists, analyzed different types of learning in mice with the human version Foxp2. There are two fundamentally different types of training - declarative And procedural. Declarative learning requires conscious control over each action and awareness of its meaning. Procedural learning occurs through automatic repetition of actions. In the experiment, normal mice and mice with the human variant Foxp2 had to go through a maze using different types of training. Procedural learning occurred by requiring the rodents to always turn right to find a treat. In another version of the task, which involved declarative learning, the treat was always placed in the same part of the maze, but since the mice were launched into it from different directions, they had to take this circumstance into account and remember the location of the reward, relying on additional external cues.

When the types of learning were examined separately, there was no difference between the two groups of mice: both groups performed about the same on the task. Hum mice gained a clear advantage over normal mice if they were first trained in a “declarative” maze and then moved to a “procedural” maze. Humanized mice appear to improve the transition from declarative to procedural learning. According to experimenters, this feature of the functioning of the nervous system of mice may demonstrate changes in the brain of people that have adapted it to speech. Scientists, in particular, believe that in hum mice the balance of declarative and procedural learning is shifted towards procedural learning, while in normal mice it is vice versa. Researchers call the phenomenon of rapid switching from declarative learning to procedural learning with an increase in the success of the latter proceduralization.

This effect of amino acid substitutions in Foxp2 became possible because this protein regulates a large number of genes and ultimately controls the development of the striatum, a part of the brain necessary for learning. Human version Foxp2 in striatal neurons, it lengthens dendrites and also increases long-term depression ( long-term depression- V.L.) signal conduction in neurons and neuroplasticity, which also has a beneficial effect on brain activity. Apparently, stronger connections are formed in the brain, which perform their function more reliably. The result of these changes is a better integration of learning processes into behavior patterns. Proceduralization does not speed up the “automation” of a skill, otherwise hum mice would gain a great advantage over normal mice already at the stage of isolated testing of different types of learning. It allows you to master a skill and subsequently learn similar actions at an accelerated pace, at an automatic level, that is, it “treads the path” for other information. In principle, this is very similar to learning to speak, when a child, having mastered the basics, begins to learn on his own, literally on the go, including constructing words independently.

Perhaps the most notable contribution FOXP2 in the evolutionary history of our species is proceduralization of our learning, which simplified not only speech. It could lead to more efficient creation of tools, the development of cooking methods, and the emergence of other important components of our culture. If you give free rein to your imagination, you can imagine that modern civilization arose thanks to two amino acid substitutions in the FOXP2 protein, and this is a rather exciting thought.

Literature

Simon E. Fisher, Faraneh Vargha-Khadem, Kate E. Watkins, Anthony P. Monaco, Marcus E. Pembrey. (1998). Localization of a gene implicated in a severe speech and language disorder. Nat Genet. 18 , 168-170;
Kate E Watkins, David G. Gadian, Faraneh Vargha-Khadem. (1999). Functional and Structural Brain Abnormalities Associated with a Genetic Disorder of Speech and Language. The American Journal of Human Genetics. 65 , 1215-1221;
D. Tsui, J. P. Vessey, H. Tomita, D. R. Kaplan, F. D. Miller. (2013). FoxP2 Regulates Neurogenesis during Embryonic Cortical Development. Journal of Neuroscience. 33 , 244-258;
G. M. Sia, R. L. Clem, R. L. Huganir. (2013). The Human Language-Associated Gene SRPX2 Regulates Synapse Formation and Vocalization in Mice. Science. 342 , 987-991;
Wolfgang Enard, Molly Przeworski, Simon E. Fisher, Cecilia S. L. Lai, Victor Wiebe, et. al.. (2002). Molecular evolution of FOXP2, a gene involved in speech and language. Nature. 418 , 869-872;
F Nottebohm. (1981). A brain for all seasons: cyclical anatomical changes in song control nuclei of the canary brain. Science. 214 , 1368-1370;
I. Teramitsu, S. A. White. (2006). FoxP2 Regulation during Undirected Singing in Adult Songbirds. Journal of Neuroscience. 26 , 7390-7394;
Thompson C. K., Schwabe F., Schoof A., Mendoza E., Gampe J., Rochefort C., Scharff C. (2013). Young and intense: FoxP2 immunoreactivity in Area X varies with age, song stereotypy, and singing in male zebra finches. Front. Neural Circuits. 7 , 24;
Sebastian Haesler, Christelle Rochefort, Benjamin Georgi, Pawel Licznerski, Pavel Osten, Constance Scharff. (2007). Incomplete and Inaccurate Vocal Imitation after Knockdown of FoxP2 in Songbird Basal Ganglia Nucleus Area X . PLoS Biol. 5 , e321;
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How is it that we humans can speak, but our fairly close relatives, chimpanzees, cannot? American experts conducted a large-scale study in which they tried to figure out what was the real reason for such a critical difference. Is brain development so important over the years, or is our genes responsible for everything?

Verbal communication between people is considered one of the main distinguishing features of man, separating him from the rest of the animal world. Let this boundary be conditional and animals still have certain manifestations of speech (as well as awareness, perception of spoken and audible sounds). But the indisputable fact is that they do not reach the human level.

What is unique? Homo sapiens, geneticists from the Universities of California at Los Angeles (UCLA) and Emory University decided to find out for sure. They suggested that our genes were to blame. However, scientists were, of course, far from the first in this, but this group of specialists was the first to conduct such an extensive study of the genetic basis of the appearance of speech in people.

It has been known for quite some time that the central gene responsible for the proper development of speech in humans is FOXP2. This gene encodes a protein of the same name, thanks to which FOXP2 can control the functioning of other genes.

Previous research has shown that when this gene is inactivated, people develop serious problems with speech (forming sentences) and pronunciation of sounds.

However, FOXP2 is also present in some animals (birds, reptiles and even fish). Logically, it turns out that he is not responsible for the appearance of speech in a person. Some scientific groups began to look for other “speech genes,” while others continued a detailed study of the work of FOXP2.

Further research showed that FOXP2 remained almost unchanged during mammalian evolution (up until the time of the human-chimpanzee split). However, about 200 thousand years ago the gene began to acquire its “human” characteristics.

The latter was established by a group of German scientists in 2002. Biologists then discovered that in chimpanzees, the proteins encoded by a version of this gene have some differences from humans. This may mean that FOXP2 functions differently in humans. Hence the unique linguistic abilities.

Another step towards understanding the processes taking place was taken this year by geneticists from the Max Planck Institute for Evolutionary Anthropology (Max-Planck-Institut für evolutionäre Anthropologie). They inserted the human version of the gene into mouse DNA.

Of course, this did not make the rodents speak like humans: after all, the ability to speak is a complex skill. But studies conducted at that time showed that the vocalization of animals had changed. In addition, in the parts of the mouse brain (those associated with speech in humans), neurons changed their structure and activity. And this is already something!

A more detailed study was carried out by a group of scientists led by Genevieve Konopka and Daniel Geschwind from the University of California in Los Angeles. Biologists grew colonies of brain cells in Petri dishes that lacked the FOXP2 gene.

Then the human version of the gene was introduced into one part of the cells, and the chimpanzee version into the second. After this, specialists monitored gene expression, the process of translating DNA information into working cell proteins, and recorded which genes were affected by these changes and how.

In their article in the journal Nature, scientists write that out of hundreds of genes subject to FOXP2, they were able to isolate 116 that responded differently to the activation of the human version than to the gene taken from monkeys. “By identifying the composition of this group, we have a set of tools that allow us to influence human speech at the molecular level,” says Konopka.

This set of genes was also likely involved in the evolution of speech and language, since many of its components control brain development or are associated with cognitive abilities. Some genes determine the appearance and control the movement of tissues of the face and larynx (which, as is known, are actively involved in articulation).

Geschwind's preliminary studies of the evolution of those same 116 genes showed that they had approximately the same history. “Perhaps they changed all together, as if in conjunction,” the scientist argues.

Daniel also notes that despite FOXP2's proven importance, he wouldn't call it the "speech gene." Perhaps FOXP2 is only part of a certain group, or it is not the first link in the chain (its work is also controlled by some hitherto unknown substance), explains the biologist.

Geschwind says this for a reason. His team conducted a second experiment: they compared gene activation in adult human and chimpanzee brain tissue. It turned out that there was a partial overlap in the work of those genes whose activity was different in the human brain and those that were controlled differently by the human version of FOXP2.

It's too early to draw any conclusions, but chances are that most of the differences are in the brain. Homo sapiens and chimpanzees (along the linguistic lineage) is explained by only two small changes in one gene. "If this is true, it would be absolutely incredible," says Wolfgang Enard of the Max Planck Institute for Evolutionary Anthropology. (We would add that this will again emphasize the smooth transition of abilities from chimpanzees to humans.)

“This work is the starting point, the basis for all future molecular studies devoted to the study of the evolution of language,” adds neuroscientist Paško Rakić from Yale.

Professor Faraneh Vargha-Khadem from University College London also commented on the current work. She deals with speech disorders in patients caused by genetic abnormalities (and in the activity of FOXP2 in particular).

The professor agrees with the conclusions of the current scientific group and notes that her patients often have a curved shape of the lower part of the face (which once again confirms that the influence of FOXP2 is multifaceted). Perhaps chimpanzees cannot speak due to the same physical abnormalities. A person could not dance if he did not have legs, compares Vargha-Khadem.

Yes, none of our smaller brothers, including chimpanzees so close to us, can communicate as meaningfully and fully, but at the same time horses, for example, use some semblance of words, monkeys seem to understand grammar and distinguish voices, and meerkats - the intonations of their relatives . Maybe they could put their thoughts into words, but they do not have the appropriate genetic prerequisites.

Faraneh also supports Daniel on the issue of a comprehensive approach to speech development in people. You shouldn't concentrate on just one gene and its many agents, she says.

In addition, Vargha-Khadem suggests that FOXP2 gave humans only the physical ability to speak, but this does not explain how abstract ideas materialized into words in the ancient human brain, or how higher cognitive skills emerged. And this still remains to be dealt with.

However, scientists still have a very long time to work with pronunciation itself. After all, if you think about it, “the movement of all those muscles that are responsible for pronunciation is also a small miracle,” says Vargha-Khadem. In order to reproduce sequences of sounds so that they are understandable to the listener, you also need to go through a very long path of development.

No special, incredible benefits have yet been discovered in humans. Maybe some animals are already moving along this path, gradually and imperceptibly catching up with people?