About the harmlessness of transgenic animals and the common ancestor of humans and cats
Cats and geneticist
In 1995, he published the book "Cats and Genes", in which, using the example of pets of various colors, sizes and characters, he explained the complex laws of genetics in an accessible way. The correspondent of "RR" met with the scientist and learned how seals help a person to better understand himself.
How can a blonde convince a brunette husband that a son born blonde is really their common child, and not conceived on the side of a blond lover? It turns out that it is not necessary to conduct a genetic examination at all. It is enough to understand the mechanisms of gene inheritance and the distribution of recessive and dominant traits in the offspring. It can be explained for a long time and scientifically difficult, but it is possible in simple human language.
So one day the doctor of biological sciences Borodin did. In the book "Cats and Genes", he describes how, using the example of cats and other animals, he explained to one desperate woman why her children do not have to be like her husband: "I wrote a detailed letter in which, with reference to a biology textbook for the 9th grade, I explained why the child was born blonde. Two weeks later I received a reply with a “huge thank you". It seems to me that I have not done so little in my life if, thanks to my writing – thanks to my science –peace has been restored in at least one family."
– In your book and in lectures, you noted that you do not study cats, but simply use them to explain the laws of genetics in an accessible way. Why are cats better suited for this than dogs, pandas or, say, reptiles?
– The most accurate definition of genetics was once given by Jerzy Lez: "Genetics is a science that explains why a child looks like his father if he really looks like him, and why he doesn't look like him if it happened that way." To explain the similarities and differences, contrasting signs are needed: not higher – lower, but naked – fluffy, yellow – green.
It so happened that the cats living with us differ from each other in just such contrasting, qualitative characteristics: in color, length and texture of the coat. These differences are clearly visible and controlled by a small number of genes, so the pattern of their inheritance is very simple.
The color of agouti – gray with stripes or streaks – dominates over black, tiger pattern over marble, short coat over long. Pandas and reptiles have few such signs.
Another important illustrative advantage of cats: quite often two individuals, if they are not pedigreed, differ from each other only in one feature – color or length of hair – and are otherwise similar. This distinguishes them from dogs, which always bear the imprint of a breed (or several breeds) and differ in several ways at once. Therefore, it is the cat, not the dog, that is the ideal example for explaining the basics of genetics – Mendel's laws.
Unlike humans, cats have a black gene – not dominant (A), but recessive (a) – VM
– So, the cat is a great illustration, and did it help to make any discoveries, for example in the field of evolutionary biology?
– Sequencing of the genes of most felines – from the lion to the domestic cat – allowed us to recreate a picture of their strikingly rapid, in just 16 million years, evolution, coupled with repeated migrations from one continent to another. A broader analysis of predatory animals has brought interesting results. It turned out that hyenas are closer to cats by origin than to dogs. Finally, a global tree of mammals was created, from which it follows that the last common ancestor of a cat, and with it a horse, a bat, a whale on the one hand, and a man, and with him a mouse, a hamster and a hare, on the other hand, lived on Earth 97.4 million years ago. And what is most remarkable, from comparing the genomes of his modern descendants, including us and our cats, we can simply deduce how he looked and what kind of lifestyle he led. And after all, this most common ancestor is not something abstract, it was a real animal, a small animal that lived underground, led a nocturnal lifestyle and therefore had a wonderful sense of smell, but did not distinguish colors. And so she was our grandmother and your cat's grandmother at the same time.
– About migration… Some experts believe that cats could not move so quickly across continents without human intervention. So, the study of these animals can tell a lot about how man traveled around the planet?
– This is a question of genogeography. As a science, it was created by the Soviet geneticist Alexander Serebrovsky back in the 1920s and applied it to chicken populations. But the first truly global genogeographic study was initiated by the English biologist John Haldane project to study cat populations. He revealed very interesting features of the migration of cats together with humans in historical times. That is, thanks to these animals, we were able to understand how man settled. Also, the work of Haldane's students and followers helped to establish how the main factors of evolution influenced cat populations: selection, isolation, gene drift. For example, an unexpected phenomenon of industrial melanism was discovered: there are more dark cats in cities than in villages.
– Scientists have studied the cat inside and out: deciphered its genome, cloned, modified... Is there anything left to study here at all – can these animals still benefit science?
– It's amazing, but with all the success of genetics and molecular biology, we still can't answer a simple children's question: where do zebra, tiger and, of course, cats have stripes on their skins? But in fact, this is a key issue of developmental biology and biology in general. Why do some genes work in some cells and others in others? That is, we know it in general terms, but the devil is in the details.
We understand why different genes work in different tissues. And this understanding – the identification of the role of transcription factors (proteins and RNA) and epigenetic modifications of the genome in the control of developmental processes – can be considered one of the main breakthroughs in modern biology.
Probably, these same factors determine why the same genes work differently in different cells of the same tissue and how stripes and other patterns are formed on the cat's body, but we still do not understand the details of this process and do not even know for sure whether these factors are acting here or what-then others.
– Experiments on animals often cause people to resent. Scientists answer this simply: "If we didn't torture the animal, we would have to torture a person." Were there any important and, perhaps, not very humane experiments on cats that made a serious contribution to science and saved a person at the same time?
– As far as I know, mostly neurophysiologists have experimented on cats. I don't know exactly what important they discovered there on these animals, since I work in another field.
Now, with the development of non–invasive research methods – tomography and the like - and the establishment of strict rules for the treatment of animals, scientists generally stop torturing anyone. Many studies are conducted on cell cultures.
What still pleases me is that cats and dogs as models for experiments have completely gone out of fashion. And it happened for purely scientific reasons. Reproducibility is required from the experiment. And it is possible only when working with pure-line, genetically identical animals. There are pure-line mice, rats, hamsters, danio-rerio fish. And there are no pure-line cats and there cannot be. So there is no need to experiment on them.
– I can't help but ask a question about GMOs and mass hysteria about this. What is genetic modification and why should people not be afraid of transgenic products? Genetic engineers have also worked on cats, but surely a genetically modified individual is no more harmful than an ordinary one?
– A genetically modified cat differs from a normal one only in that if you direct ultraviolet light at it, it will glow red. The cat glows because there is a red fluorescent jellyfish protein in its cells. And she has this protein not because she ate a jellyfish, but because scientists isolated the gene of this protein from the genome of a jellyfish and then inserted it into the genome of a cat by complex tricks. This is a genetic modification.
If you play with a transgenic cat and even eat it, you won't light up from it. Transgenes are no different from normal genes, they are not transported by airborne droplets or, how should I put it better, by the gastrointestinal tract from one animal to another or from plants to animals. When you eat cucumbers, you also eat cucumber genes. However, do not become green and pimply.
In general, regarding hysteria with GMOs, one should not turn to geneticists, but to psychiatrists and political strategists. For us, everything is clear here: genetic engineering is the greatest achievement of science of all times and peoples and the only means to feed the current and future population of the Earth on existing areas and with a minimum of environmental pollution.
With the current rules for the creation and use of GMOs, harmful consequences for human health and the biosphere are theoretically extremely unlikely. For decades of using transgenes, no dangerous effect has been detected. Only the blatant illiteracy of politicians and their advisers or, even worse, their criminal lies for the sake of solving minor momentary problems can explain the bans on GMOs in Europe, and now in our country. So ask political strategists how and why this hysteria is inflated, and psychiatrists – why people are so easily led to silly horror stories like the harm of vaccinations and GMOs and turn a blind eye to really serious problems, such as climate change and the spread of drug-resistant pathogens.
– Last year you said that you were going to launch a project related to the genogeography of cats – you would collect their genetic material and make a map of the prevalence of different phenotypes in the regions of Russia and other countries. Are there any results?
– The project is gradually unfolding. Last year, as part of the summer school of the Dynasty Foundation, my colleagues, led by Professor Yuri Aulchenko, organized and carried out a wonderful genogeographic project. They asked the participants of this school to photograph as many cats as possible in their towns and villages, take wool samples from some of them and bring them to Pushchino.
The students performed this task brilliantly. They uploaded about 400 photos to the group "Genogeography of cats, summer biological school" in the VKontakte social network. Based on the analysis of these images, they built a phylogenetic tree of the cat populations of Russia. And from the collected wool samples, mitochondrial DNA was isolated, sequenced and genotypes typical of different regions of our country were determined.
So now it will be possible to determine from which city this sample is from, and, accordingly, from where the criminal dragged it, by a sample of wool, for example, by a cat's hair stuck to the criminal's pants. However, few cities have been studied so far, so the tree is not particularly accurate, and the diagnosis is limited. Now a similar project is being done at the Novosibirsk Center "DIO-GEN". In general, anyone can join these projects and do a lot of useful things both for science and for solving crimes.
– What exactly are you working on now, which animals or insects are you researching?
– I am studying the behavior of chromosomes in meiosis, that is, during the formation of germ cells. Accordingly, I am interested in animals that have something interesting in the set of chromosomes. These are ordinary Siberian shrews and Argentine tuco-tuco, which manage to live and reproduce successfully, having many different rearrangements in the chromosome set. These are hybrids of voles, in which meiosis stops because the chromosomes cannot find each other, although they try their best. These are voles themselves with very old, older than 250 million years, and worn–out sex chromosomes, on the one hand, and guppy fish with young, no older than 30 million years, sex chromosomes, on the other… But, as I have already said, when it comes to a popular science book, it is still better to help the reader wade through the wilds of genetics using the example of cats.
– And if there were no cats, by the example of whom or what would you explain genetics?
– The genetics of many domestic animals are now well researched. I would explain on horses or guppy fish.
– As I understand it, you have a scientific interest in cats first of all. And how do you treat them just as a person? Do you have a cat at home?
– I treat cats very well on the streets and in the homes of relatives and friends. And he endured at home when the children dragged them. Now my grandson lives at home. Do you want me to explain why and how a grandson is better than a cat?
– Surely you have some funny or instructive story about a cat, or maybe about a grandson with a cat…
– It's better about a friend with a cat. It used to be cold in Siberia, and meat was rarely sold in stores. Therefore, in the autumn people bought a lot of meat at once, cut it into pieces and stored it on balconies. A friend of the professor had a cat whose name was Cat. He lived on the fifth floor. In winter, he walked on the balconies and sometimes returned with a piece of meat, which he honestly gave to the owner. The owner, of course, was tormented by conscience, but since it was somehow inconvenient to walk around the neighbors and ask: "Is this your piece of meat?", he gave the meat to the Cat. But so that the beast does not know that this is the same meat that he just brought. And he always scolded the cat for pedagogical reasons.
Pavel Borodin
Doctor of Biological Sciences, Head of the Laboratory of Recombination and Segregation Analysis of the Institute of Cytology and Genetics SB RAS. One of the main popularizers of biology and genetics in Russia. Author of school textbooks and numerous articles in domestic and foreign scientific journals. His first non-fiction book titled "Studies about Mutants" was published in 1983. Later he published a monograph "Cats and Genes", which was widely recognized and reprinted several times. Now Borodin is studying the behavior of chromosomes during the formation of germ cells in voles and guppy fish.
Portal "Eternal youth" http://vechnayamolodost.ru23.04.2014