The book "DNA. History of the genetic revolution "

    imageGet to know the history of the genetic revolution told by James D. Watson, Nobel Prize winner. The brilliant scientist sends us on the greatest scientific journey, covering all the milestones of the genetic revolution, from the discovery of the double helix to the discoveries of the last decade.

    The discovery by mankind of the double helix of DNA in significance can only be compared with the achievements of the Enlightenment. Natural selection still works, but gene therapy has already become a reality. What awaits us next?

    There are practically no areas of science and activity that to one degree or another would not be related to genetics: gene editing, epigenetics, agrochemistry, genomics, and cancer research are only the tip of the iceberg.

    Chapter 11

    People tend to be interested in their own ancestors: who they are and where they came from. The United States is a nation formed from many generations of immigrants, so the Americans have such information traction is particularly strong. In recent years, the genealogical excitement is heated up on the Internet, which also allows us to conditionally evaluate the popularity of a particular phenomenon. So, Google gives out more than a million matches on the search query “genealogy”. DNA allows you to compare the genetic fingerprints of individuals and thus allows you to conduct targeted genealogical investigations; so, one of such projects allowed Jill and Ivanova to clarify whether Anna Anderson was a relative of the Romanovs (no, she was not). But the genealogy can be clarified in a wider context, to find connections by comparing the DNA fingerprint of an individual and whole populations.

    Brian Sykes of Oxford plunged into his own story, analyzing his DNA. Knowing that both the surname and the Y chromosome are transmitted through the male line, he suggested that all male namesakes should also have the same Y chromosome — the one that belonged to the very first man who bore this surname. Of course, such a link between the Y chromosome and the surname is broken if the name is given arbitrarily, if the man changes his name for any reason, and also (as happens with many boys) if the boy takes the name of another biological father. For example, if a mother secretly became pregnant by a milkman, then her son, with a high degree of probability, will have the same surname as her husband.

    Professor Sykes contacted 267 his namesakes and was able to obtain forty-eight samples for analysis. It turned out that 50% of their Y chromosomes are really identical to his “Sayksovskaya” chromosome, in the rest there were signs of adultery by one or more Mrs. Sykes. Since the origin of this family name is documented and its history can be traced for at least seven centuries, it is possible to calculate the “infidelity coefficient” for each generation. On average, a completely decent 1% per generation is obtained - this means that 99% of Sayksov's wives in each generation successfully resisted the temptation of adultery.

    When Sykes founded his own company, Oxford Ancestors, which provides genetic fingerprinting services, among his clients was the John Klof Genealogical Society, whose members trace their genealogy to the British with that last name who immigrated to Massachusetts in 1635. Society even found out that his ancestor named Richard (from the Welsh line) was knighted for his exploits in the Holy Land during the crusade. However, they lacked historical evidence that would allow their families to be associated with namesakes on the other side of the Atlantic. Sykes company analyzed the Y chromosome of Massachusetts Klofov, as well as genealogy from a direct ancestor of the male line of Sir Richard. The two lines were indeed identical - a fact in favor of the Massachusetts branch. Nevertheless, not all American Klofov found a reason for joy. It turned out that members of society from Alabama and North Carolina are not related not only to Sir Richard, but also to Massachusetts Clofam.

    Today, websites of modern personalized genetic genealogy companies, such as 23andMe and, are replete with remarkable stories about how people find their long-lost relatives — brothers and sisters, parents, cousins, and children. offers a service that allows you to restore a client's pedigree up to the 1700s just by sample DNA.

    In a typical American daytime talk show with presenters such as Mori Povich or Jerry Springer, a nervous kind of young women and men often perform. The presenter opens the envelope, looks meaningfully at the pair, and then reads the card. The woman covers her face with her hands and starts crying hysterically, and the man just jumps up with delight and triumphantly throws up his fists. Either the woman begins to jump, victoriously pointing at the man, and he sits, slouching, in his chair. In both cases, your attention is offered an even more exotic version of the use of genetic fingerprinting - exclusively entertaining.

    Yes, perhaps all daytime shows are staged, but paternity analysis is a serious matter with long traditions. Since the dawn of humanity, the life of everyone, his social, psychological and legal being, depended to a large extent on who his father was. Therefore, naturally, under the analysis of paternity began to bring a scientific basis since the time began to develop genetic methods of personal identification. Before the advent of molecular genetics, the most authoritative marker of paternity from a scientific point of view was blood. The principles of inheritance have been well studied and quite understandable, but given the fact that blood groups are only once, twice, and the number is turned off, the resolution of this method was small. In practice, a blood test more or less successfully detected cases of false accusations of paternity, but did not allow to find out who the real father was. If our blood types are incompatible with you, then I’m definitely not your father, and if they are compatible, it still does not prove that I am your father; the same applies to all other men who, like me, have the first group of blood. With the use of other markers, along with the well-known classification by blood group (ABO), the resolution of this method increases, but by statistical measures it still cannot be struck with STR-typing; genetic fingerprinting using the STR method rather easily allows a positive paternity analysis. With the use of other markers, along with the well-known classification by blood group (ABO), the resolution of this method increases, but by statistical measures it still cannot be struck with STR-typing; genetic fingerprinting using the STR method rather easily allows a positive paternity analysis. With the use of other markers, along with the well-known classification by blood group (ABO), the resolution of this method increases, but by statistical measures it still cannot be struck with STR-typing; genetic fingerprinting using the STR method rather easily allows a positive paternity analysis.

    Genotyping technology is evolving so quickly that mail order paternity companies can literally thrive. On the streets of some cities there are giant billboards advertising local service of such analyzes with a completely shameless slogan: "And who is dad?". You pay, and such a company sends you a DNA test kit with a swab to take a cell sample from your mouth. You send the cellular material to the laboratory by mail, and DNA is extracted from it. The fingerprint of the child is compared with the parent; any STR repeats present in the child and absent in the mother are definitely obtained from the father, whoever he is. If the fingerprint of the alleged father is not one of these repeats, then he is not the father. If all are present, then the number of repetitions allows to quantitatively express the probability of coincidence on the so-called paternity index (PI). Thus, it is estimated with what probability in these STR-repetitions there may be those that are not received from the father, and the indicator varies depending on how much this STR is distributed in the population. The PIs of all short tandem repeats are multiplied together and give a total paternity index.

    Of course, most paternity tests are performed under conditions of maximum confidentiality (unless of course you are not a talk show participant), but one of the recent analyzes hit all the headlines, considering how great the historical interest is in the identity of the alleged father. It has long been suspected that Thomas Jefferson, the third president of the United States and the main author of the Declaration of Independence, was not only one of the founding fathers; he also allegedly had one or more children from his slave Sally Hemings. For the first time such an accusation was made in 1802, just twelve years after the birth of her first son Tom, who later took the name of one of his masters - Woodson. In addition, the last son of Hemings, Estonia, was very similar to Jefferson. This issue was solved with the help of DNA analysis.

    Jefferson had no legitimate male heirs, so it’s impossible to identify markers of his Y chromosome. However, researchers took DNA samples from men originating from Field Jefferson, who was the father’s uncle to Thomas Jefferson (and therefore the Y-chromosomes were identical with the president), and compared them with the DNA samples of men descendants of Tom and Eston. The analysis showed a clear Jefferson fingerprint on the Y chromosome, but his fingerprint was not found in the descendants of Tom Woodson. For the first time, Jefferson’s reputation stood up. However, in the descendants of Aston Hemings, the signature of the Y chromosome was uniquely Jeffersonian. True, DNA analysis cannot with certainty show what the source of this chromosome is. It is not known whether Thomas Jefferson, or any other men of the Jefferson family, was really Aston’s father. who could also have a connection with Sally Hemings. In fact, certain suspicions fell on Ishem Jefferson, the nephew of the president.

    Even if the nation has been honoring you for centuries, you still can’t hide from the harsh reality that DNA analysis opens up. Neither nobility, nor any money will help. When the Brazilian model Luciana Morad announced that her son's father was Mick Jagger, the Rolling Stones singer did not recognize this and demanded that DNA be analyzed. Jagger may have been bluffing, hoping that the threat of a criminalistic conclusion of the case would weaken Senorita Morad’s determination, and she would withdraw the claim. But she did not. The tests were positive, and Jagger was legally obliged to participate in the upbringing of his son. Boris Becker also tested for paternity about a girl born to the Russian model Angela Ermakova. The tabloids earned great money on the story of how a star tennis player decided that he was slandered by the Russian mafia. Details of the scheme on which this conspiracy was allegedly carried out, it is better to leave it on the pages of tabloids. Suffice it to say that the DNA test was positive, Becker recognized paternity and pledged to support his biological daughter.

    Глава 12

    Ideology of any kind and science are not the best comrades. Science can really reveal unpleasant truths, but it is fundamentally important that these are truths. Any efforts, both malicious and good, are destructive if they are aimed at hiding the truth or hindering its disclosure. Too often in our free society, scientists who want to deal with issues with political overtones are forced to pay too high a price for this. When in 1975, E. O. Wilson (EO Wilson) from Harvard published his work Sociobiology: A New Synthesis, which is a detailed analysis of the evolutionary factors underlying the behavior of animals, ranging from ants, the study of which the scientist specialized in, and ending people, he was attacked by the professional community and the media. In 1984, in response to the work of Wilson, a book was published, the title of which spoke for itself: “Not in Our Genes” (“Not in our genes”). E.O. Wilson was even physically attacked when protesting against the genetic determinism found in his work poured water on him from a pitcher during a public meeting. Similarly, the work of Robert Plomin (Robert Plomin), devoted to the influence of genetics on human intelligence, to which we turn next, caused such a hostile reaction among American scientists that the author had to leave the University of Pennsylvania and leave for England. provided for in his work, they poured water from a pitcher during a public meeting. Similarly, the work of Robert Plomin (Robert Plomin), devoted to the influence of genetics on human intelligence, to which we turn next, caused such a hostile reaction among American scientists that the author had to leave the University of Pennsylvania and leave for England. provided for in his work, they poured water from a pitcher during a public meeting. Similarly, the work of Robert Plomin (Robert Plomin), devoted to the influence of genetics on human intelligence, to which we turn next, caused such a hostile reaction among American scientists that the author had to leave the University of Pennsylvania and leave for England.

    Passions inevitably boil when science threatens to destroy or change our ideas about human society and about ourselves — our species and personal identity. Can I imagine a more radical question than the question of what makes me stronger: a nucleotide sequence A, T, G and C, inherited from my parents, or an experience that I gained since my father's sperm cell merged with the egg my mother many years ago? The forefather of eugenics, Francis Galton, was the first to formulate the question of whether heredity or upbringing is more important. The implications of this issue affect to a lesser extent philosophical and more practical areas. For example, are all mathematics students born with equal abilities? If not, maybe Isn't it worth spending time and money on teaching differential calculus to people like me who are just not able to assimilate this information? In a society based on the ideals of egalitarianism, the assumption that people are not born equal is unacceptable to many. The point is not only that much is at stake, but also in the difficulty of solving relevant problems. People are influenced by both genes and the environment. How to separate these two factors to determine the degree of influence of each of them? If we were dealing with laboratory rats, we could conduct a series of experiments, ensuring their reproduction and rearing in certain uniform conditions. But, fortunately, people are not rats, so in our case the answer is much harder to find. The combination of the importance of the question and the extreme difficulty of finding an adequate answer stirs up this centuries-old non-dying dispute. Nevertheless, a free society should not shy away from honestly posing honest questions. It is extremely important that the discovered truths be used only for the good of man.

    Due to the lack of reliable data, disputes about the priority of heredity or upbringing were completely subject to the changing winds of social change. At the beginning of the twentieth century, during the heyday of the eugenic movement, heredity was considered the leading one. However, when the fallacies of eugenics became apparent, resulting in the horrific experiences of the Nazis, upbringing began to win back the position. In 1924, John Watson (we are just namesakes), the founder of such an influential direction in American psychology as behaviorism, expounded his point of view on education in the following way:

    Give me a dozen healthy, well-developed babies and my own special world in which I will raise them, and I ... choosing a child at random, can make it at my own discretion a specialist of any profile - a doctor, a lawyer, a trafficker, or even a beggar or a thief - out depending on his talents, inclinations, professional abilities and race of his ancestors.

    The perception of a child as a “tabula rasa” - a clean blackboard on which any future can be traced using experience and education, was well combined with the liberal situation in the 1960s. Genes (and the determinism caused by them) were not considered. Throwing off heredity, psychiatrists claimed that mental illness is caused by a variety of stresses caused by environmental factors. Such a statement sowed guilt and paranoia among parents whose children suffered from similar disorders. “What did we do wrong?” They asked. The tabula race paradigm remains popular among politically biased advocates of some of the most unfounded views on human development. For example, to some unshakable participants in the women's movement, the assumption of biologically or genetically determined sex differences and mental abilities seems simply unthinkable: men and women are equally capable of solving any problem, period. The fact that men are stronger in some areas, and women in others, according to these theorists, is the result of multidirectional social pressure: a man is destined for one destiny, and a woman for another, and everything begins with wrapping a girl in a pink blanket, and a boy in blue.

    Today we are witnessing a departure from the extreme, attributing the decisive influence to education. It is no coincidence that this departure from behaviorism coincides with the first attempts to study the genetic basis of behavior. As we learned from Chapter 9, for many years the development of human genetics lagged behind the development of the genetics of Drosophila and other creatures, but the completion of the Human Genome project, as well as the analysis of tens of thousands of human genomes carried out over many years, especially in the diagnosis and treatment of hereditary diseases. However, some of the efforts of molecular biologists have been directed to questions not related to medicine. So, Robert Plomin, used this approach to identify genes that affect IQ, working at the annual meetings of the smartest schoolchildren from all over the country in Iowa. Considering, that the average IQ among these particularly smart kids was 160 points, it was here that it was worth starting the search for genes that might be responsible for mental abilities. Robert Plomin compared their DNA with samples of “normal” children with a medium IQ, as we have with you, and really found a weak connection between the genetic marker on chromosome 6 and the extremely high IQ. This suggested that one or more genes in this region could somehow contribute to a higher IQ.

    Of course, any mechanism that determines such a complex trait is most likely associated with many genes. Today, scientists searching for genes associated with complex behavioral characteristics have much more powerful tools. In 2014, the results of an extensive genome-wide study of associations were published, in which more than 100,000 people took part. Conclusions were mixed: on the one hand, the data pointed to three specific genes or regions (in chromosomes 6, 8, and 10) associated with cognitive abilities. On the other hand, the perceived influence of these “smart genes” is incredibly small, and the variable region of DNA in chromosome 6 is too far from the region indicated by Robert Plomin. As we saw earlier in the schizophrenia example,

    Another way to search for genes associated with intelligence involves identifying genes that function abnormally (or absent) in people with mental retardation or other forms of cognitive impairment. In recent years, this approach has begun to produce results. Hans-Hilger Ropers (Hans-Hilger Ropers), a specialist in the field of medical genetics from the Research Institute of Molecular Genetics of the Society. Max Planck, comprehensively analyzed the genomes of 136 families from Iran and other countries whose children were born from parents of consanguinity, and identified more than fifty new genes related to mental disability, many of which point to important biological pathways involved in the process. normal brain development.

    But even a genetically determined predisposition may not appear if you were brought up in an environment where the focus is not on learning and intellectual development, and not on watching cartoons. Nevertheless, the discovery and recognition of any molecular background of mental abilities is a step forward that could only be realized by revolutionary genetic discoveries.

    Before working with DNA markers, behavioral genetics specialists were mainly engaged in the study of twins. Twins are of two types: fraternal twins develop from different eggs fertilized by different spermatozoa, and identical twins from a single fertilized egg, which at an early stage of development (usually at the stage of eight or sixteen cells) is divided into two. Fraternal twins are no more genetically alike to each other than ordinary brothers and sisters, while identical twins are genetically identical. Therefore, identical twins are always of the same sex, and fraternal twins can be heterosexual. Surprisingly, this fundamental difference between the two types of twins was realized recently. Francis Galton, who in 1876 was the first to propose using twins to determine the relative influence of heredity and upbringing, did not yet know about this distinction (the scientific justification for which was developed only two years earlier) and mistakenly suggested that twins of different sexes can develop from one fertilized egg. Nevertheless, from his later publications it followed that he had already taken into account the data obtained by scientists.

    Identical twins are born around the world with a frequency of about four times per thousand, and this event can only be considered accidental. On the other hand, the appearance of fraternal twins may be due to heredity, and the frequency of their births may vary depending on the population: most fraternal twins are born in Nigeria - forty cases per thousand pregnancies, whereas in Japan there are only three per thousand pregnancies.

    Standard studies of twins are usually based on the assumption that both members of a same-sex pair of identical or identical twins grow under the same conditions (that is, they receive a similar “upbringing”). Suppose we are interested in an easily defined characteristic, such as growth. If RB1 and RB2 fraternal twins received the same amount of food, care, etc., then any difference in growth could be explained by some cumulative effect of genetic differences and minor differences in lifestyle (for example, RB1, unlike RB2, always drank milk ). However, if the same logic is applied to identical twins OB1 and OB2, then their genetic identity will eliminate genetic variation as a factor, that is, any differences in growth can be explained by small differences in the environment. Other things being equal, there will be smaller differences in growth among identical twins than among fraternal twins, and the degree of compliance with this pattern will give an idea of ​​the influence of genetic factors on growth. Similarly, a closer resemblance of identical twins in IQ versus fraternal twins reflects the influence of genetic variability on the intelligence quotient.

    Such an analysis works in a similar way when studying the inheritance of genetically determined diseases. Gemini is called concordant if both have a disease. A higher concordance in pairs of identical twins as compared to a couple of opposed ones should indicate that the disease is largely genetically determined: for example, the contradictory twins in type 2 diabetes are 25% (if one of the twins is sick, in one case of the four sick and the other), while the concordance of identical twins in this disease is 95% (if one of the twins is sick, then in 19 cases out of 20 sick and the second). Hence we conclude: type 2 diabetes is largely due to genetic predisposition. Nevertheless, even in this case, the medium plays a large role;

    »More information about the book is available on the publisher's website
    » Table of contents
    » Excerpt

    For Habrozhiteley 20% discount on the coupon - DNA

    Also popular now: