Genes define who we are - and now we can manipulate them. Identical twins - like these cute girls from the annual Ohio Twin Day festival - are very important for genetic research, because they often share the same genome and even the same traits, habits, tastes, even if they were separated at birth. In Gene: Intimate History, Siddhartha Mukherjee calls the gene "one of the most powerful and dangerous ideas in the history of science." Since its discovery by Gregor Mendel, a mysterious Augustinian monk, the gene has become both a force of evil and good. In the 1930s, the Nazis used the pseudoscience of eugenics to mend the Holocaust. Today, gene therapy offers hope for the eradication of hereditary diseases and even psychological disorders like schizophrenia.
National Geographic spoke with Mukherjee, a professor of medicine at Columbia University who also received a Pulitzer Prize for his work in the field of cancer. He told many interesting things about this new weapon - or panacea - for humanity.
Your book's subtitle speaks of a "close story." Tell us what inspired you to write the history of the gene?
I have been thinking about this book for a long time. I have long been tormented by the eternal question why we are similar and not like others. In my particular case, this question revolved around mental illness. Why did two uncles and one cousin of my family suffer from him and the others not? My uncle Yagu, who lived with us, was diagnosed as schizophrenic but died long before the disorder was taken seriously.
In the 2000s, many studies were published linking schizophrenia and bipolar disorder and suggesting that there are strong familial and possibly genetic links between these mental disorders. How do genes relate to the environment? What determines their chance to influence human destiny?
You call the gene "one of the most powerful and dangerous ideas in the history of science." Expand this thought for us.
Powerful because of heredity and identity. What makes us who we are and how do we communicate this information? To what extent does inheritance determine our identity? These are very powerful questions we ask ourselves. They are also very dangerous because they raise the idea that we can control and manipulate them. What if you could change a person's identity simply by changing their genes, or could you shape a person's future by knowing their genetic makeup? The history of eugenics shows how genetics can distort the political field and how it becomes dangerous.
You and I have had identical twins in our lives: your mother and aunt and my older brothers, they are all identical twins. Why are twins so important to gene research?
Gemini is an amazing natural experiment. With a few exceptions, their genomes are identical. Therefore, how they are born, what diseases are prone to, what they have in common is a great way to find out which aspects of human nature are influenced by genes and which are not. I say influence because identical twins are obviously not identical. Their lives run differently, reminding us that biology is not a book of fate. Biology strongly influences our destiny. But she doesn't mean her. Even if you have exactly the same genomes, you will not get identical clones. "I" will remain unique.
The pseudoscience of eugenics reached its apotheosis in Nazi Germany. But I think our readers will be shocked to learn that a lot of developments on this topic have been done in America. Tell us about Carrie Buck.
I dedicated the book to Carrie Buck as she was one of the first women in the United States to be sterilized by a court order. It was suspected that she had a hereditary mental illness, and in the 1920s, to purge the population of her genes, she was imprisoned in a colony in Virginia. One of the chiefs of the colony was a man named Albert Priddy, one of the biggest advocates of eugenics through selective sterilization. Priddy went to the Supreme Court, and an authoritative judge concluded that "three generations of imbeciles will be enough, " thereby sentencing Carrie Buck to sterilization. We now know that the chances that Carrie Buck had the hereditary mental illness that Priddy was trying to eradicate was slim.
The word genocide has the root “gene”. Describe the methods used by Hitler's eugenicists and how they led to the Holocaust.
From the 1920s to the 1940s, the Nazi Party began a race purification movement in an attempt to purge the entire human race in genetic infirmaries. They tried to determine who has a hereditary "marriage": deaf, blind, people with congenital diseases. They played propaganda films in which they tried to describe how terrible the life of such people can be, trying to justify the methods of their destruction. Thus, a testing ground was laid for a much broader program of extermination in the form of the Holocaust. By the 1930s, Jewish men and women were disproportionately targeted by this race to purify the race.
There has been a great quantum leap forward in the history of the gene - DNA, which James Watson, one of the discoverers of the double helix, called the "Rosetta Stone for Unraveling the True Mysteries of Life." Why is it so important?
In the 1910s and 1920s, people started thinking about what code could carry to create organisms, fix them, and maintain them. But they didn't know its chemical form. Thomas Morgan, a great scientist who studied fruit flies, along with others, realized that genetic information is carried by chromosomes. But he didn’t know what chemicals were responsible for this transfer and why, and how exactly they transfer all this information. Therefore, a hunt has begun for a chemical that carries this information. If you could identify this substance and manipulate it, or move it from one organism to another, you could theoretically change biological, hereditary information.
The discovery that DNA carries genetic information came as a huge surprise. It was made by Oswald Avery and his colleagues at Rockefeller University in the 1940s. Then a race began to try to understand its structure. How can DNA actually carry information to create you and us? This question was answered by the structure of DNA.Later it turned out that the structure allows DNA to carry information in this incredible form: in the form of a sequence A, C, B, G, G, C, G, A and so on. Four letters convey the information needed to create a person. This ultimately led to the human genome project.
In the movie "The Servant, " African-American Abe once said: “We are the same. Just different colors. " Tell us about mitochondrial Eve.
Mitochondrial Eve is an amazing concept. The idea is that the genetic information we inherit comes from our fathers and mothers, chromosomes from each ancestor. But there is also an exception: a factory that produces energy in our cells, which also has genetic information. Only this genetic information comes exclusively from the mother. By looking at this mitochondrial information, you can trace how yours came from your mother, hers came from her mother, and so on. There is a matrilineal lineage. Humans are very young as a species, only 200, 000 years old. And if you trace the mitochondrial DNA from mother to mother, you can get to the genetic information of one woman who lived somewhere in Africa. She was not the only woman living at the time. But it was from her that all our genealogies went. Therefore, it is called mitochondrial Eve.
How do genes determine human intelligence? Is there such a connection?
One of the most controversial books in recent years has been Bell's Curve. In it, the author tries to understand the foundations of human intelligence and the extent to which human genes can influence it. If you look closely, genes do affect one aspect that we associate with human intelligence: the IQ test. But this is just one intelligence test. The Bell Curve not only tries to prove that genes influence IQ, but that if you measure the intelligence of different "races" - although this word is not entirely appropriate - you might find that Asians and Caucasians gain 10 more on these tests. 15 points.
Why is this the wrong approach? Yes, if only because the very construction of the IQ test has been disputed since the 1990s. Someone gains more in one part of the test, someone in another. Bias and emphasis determine the final score.
Is there a “gay gene”? What about gender?
We know that genetics have a powerful effect on gender. We also know that there is not a single gene that determines gender to a greater extent. There is a lot of confusion about the exact genes that determine this, but there is an influence - we learned this from researching twins. There is no “gay gene”. There may be several genes that interact with the human environment and lead to different gender biases. But there is not one gene that can be called "gay".
Now we can change the human genome at will. What are the potential benefits and dangers of genetic engineering?
We are sequencing the genome of eggs and embryos more and more and we are starting to use technologies that could potentially allow us to change the human genome. Potential benefits could include the elimination of diseases with strong genetic connotations.
The danger is that there will be unintended consequences. We will suddenly start making decisions about which human genes are preferred over others. In doing so, we run the risk of making the wrong decisions about which gene variations should not exist. Although the technology around the human genome is highly regulated, it is unlikely that the decision about which child you are allowed to have will be made at the government level. People will make decisions individually, and this is, in fact, eugenics.
What strikes you most about the gene's story, Siddhartha?
The most amazing thing is how unknown all this is to the general public. Anyone who begins to discover the history of genes will be surprised at how little history of social eugenics we know; how much we know about genes and genomes today; how we are on the verge of being able to change the human genome; and how it will be easy to do.