The book "Energy, sex, suicide: mitochondria and the meaning of life"
Hello! We have a great book by Nick Lane from the New Science series :
From time immemorial people turned their eyes to the stars and thought about why we are here and whether we are alone in the Universe. We tend to think about why plants and animals exist, where we come from, who our ancestors were and what lies ahead. Let the answer to the main question of life, the Universe and in general not 42, as Douglas Adams once claimed, but it is no less brief and mysterious - mitochondria.
They show us how life originated on our planet. They explain why bacteria reigned on it for so long and why evolution most likely did not rise above the level of bacterial mucus anywhere in the Universe. They make it possible to understand how the first complex cells arose and how earthly life climbed the stairs of ascending complexity to the heights of glory. They show us why warm-blooded creatures emerged, shaking off the shackles of the environment; why there are men and women, why we fall in love and have children. They tell us why our days in this world are numbered, why we grow old and die. They can tell us the best way to spend the sunset years of life, avoiding old age as a burden and a curse. Maybe mitochondria do not explain the meaning of life, but at least they show what it is. Is it possible to understand the meaning of life, not knowing how it works?
')
Mitochondria are small cellular organelles that produce almost all of our energy. One cell contains on average 300-400 mitochondria, that is, in the whole human body there are ten million billions of them. Mitochondria are present in virtually all complex cells. They look like bacteria, and this is the case when appearance is not deceptive. Once the mitochondria were free-living bacteria, and then - about two billion years ago - they adapted to life inside the cells. As a sign of former independence, they retained a fragment of the genome. The uneasy relationship between mitochondria and host cells defines many aspects of cell life — from energy production, the sexual process and reproduction to self-killing, aging and death.
Mitochondria is one of the many “energy stations” of cells that control our lives in the most unexpected ways.
Mitochondria - an open secret. One way or another, many have heard of them. In newspaper articles and some textbooks they are called "energy stations of life." These miniature generators, hidden in cells, produce almost all the energy we need. In a single cell, there may be hundreds or thousands of mitochondria that burn organic matter with oxygen. They are so small that a billion would easily fit in a grain of sand. With the advent of mitochondria, life received a powerful engine, already operating at high speeds and ready to use. All animals, including the most sedentary, have at least some mitochondria. Even stationary plants and algae use them as a source of additional energy, an additive to the energy of photosynthesis, which they receive from their “solar panels”.
Some have probably heard the expression “mitochondrial eve”. It is assumed that she was the mother of humanity, the last common ancestor of all living people. "Mitochondrial Eve" allegedly lived in Africa (possibly 170,000 years ago), and is also called the "African Eve." We can trace our genetic ancestry to mitochondrial Eve, perhaps because mitochondria have their own small genome, which is usually passed on to the next generation only through the egg cell, and not through the sperm cell. This means that the mitochondrial genes act as a surname transmitted through the female line, which can thus be traced; so, some families raise their lineage through the male line to Wilhelm the Conqueror, Noah, or the prophet Muhammad. Recently, some of the provisions of this theory have been challenged, but in general it has withstood. Of course, this method allows not only to identify our ancestors, but also to understand who was not our ancestor. For example, analysis of mitochondrial genes suggests that the Neanderthals still did not interbreed with Homo sapiens, but were driven out to the outskirts of Europe, where they died out.
Mitochondria are also "famous" for their role in forensic medicine. They were often used to identify people, living or dead, and some such stories had a wide resonance. As in the case of the definition of our ancestors, the method of identification is based on the fact that mitochondria have their own genes. The authenticity of the remains of Nicholas II, the last Russian emperor, was confirmed by comparing his mitochondrial genes with the mitochondrial genes of his relatives. And at the end of the First World War in Berlin, a seventeen-year-old girl was pulled out of the river, who claimed that she was Anastasia, the lost daughter of Nicholas II. The girl was sent to a hospital for the mentally ill. Analysis of mitochondrial genes, conducted after her death in 1984, put an end to seventy-year disputes, showing that she was not the daughter of Nicholas II.
If we look at the recent past, the mitochondrial analysis helped to identify the bodies disfigured beyond recognition by the people who died as a result of the terrorist attack of September 11, 2001 when the towers of the World Trade Center in New York collapsed. The same method made it possible to distinguish the "real" Saddam Hussein from his many twins. One of the reasons why mitochondrial genes are so useful is the large number of copies. The genome of each mitochondria is represented by 5–10 copies, and there are usually hundreds of mitochondria in the cell, so the total number of their genomes amounts to thousands of copies. For comparison, the genome of the cell itself is represented by only two copies (which are located in the “control point” of the cell - the nucleus). Therefore, it is possible to obtain some, even minimal, number of mitochondrial genes from almost any sample. And the fact that they are common in the child, his mother and all relatives on the maternal line, makes it possible to confirm or deny the alleged relationship.
Let's go further. There is a so-called mitochondrial theory of aging. She argues that free radicals - chemically active molecules that "leak" from mitochondria in the process of normal cellular respiration, cause aging and many diseases associated with it. The problem is that “spark formation” is not completely excluded in mitochondria. When they "burn" food under the influence of oxygen, the resulting "sparks" of free radicals can damage neighboring structures, including the mitochondrial genes themselves, as well as more distant genes in the cell nucleus. Free radicals attack the genes in our cells from 10,000 to 100,000 times a day - in other words, you have to wait for some kind of trick from them literally every second. Most of the damage caused is immediately corrected, but some attacks cause irreversible mutations, that is, sustained changes in the nucleotide sequence of the gene. With age, they accumulate in the body, and the cells with the most serious injuries die. Permanent wear and is the basis of aging and related diseases. Many severe hereditary diseases are also associated with mutations resulting from the attack of free radicals on mitochondrial genes. These diseases are often inherited in a strange and unpredictable way, and their severity varies from generation to generation, but the general rule is that they all progress inexorably with age. Usually, mitochondrial diseases affect metabolically active tissues, such as muscles and the brain, and can lead to convulsions, movement disorders, blindness, deafness and muscular dystrophy.
Some have heard of mitochondria in connection with one of the methods for treating infertility, which has been fiercely controversial. Its essence is that the fragment of ooplasm containing the mitochondria from the egg of a healthy female donor is transferred to the egg of an infertile woman (the so-called transfer or transplantation of ooplasm). When information about this method was first leaked to the media, one British newspaper published an article under the catchy headline: "Infants from two mothers and one father." It cannot be said that there is no truth in this journalistic joke. Although the child receives all the “normal” genes from the “real” mother, he receives a certain number of mitochondrial genes from the female ooplasmic donor. So, strictly speaking, babies really got the genes from two different women. Despite the fact that thanks to this method, more than 30 perfectly healthy babies were born, it was subsequently banned in the UK and in the US for both ethical and practical reasons.
Mitochondria even got into the series “Star Wars” (much to the indignation of some fans) as a rather vague justification of the famous Force, which “be with you”. In the first episodes, it was assumed that this power has if not religious, then at least a spiritual nature, but in the fourth episode it was associated with the "midi-chlorians". Midichlorians, as one Jedi popularly explained, are “microscopic life forms that live in all living cells. We live with them in a mutually beneficial symbiosis. Without midichlorians there would be no life, and we would never know what Power is. ” Both in the explanation and in the title itself there is a transparent, intentional allusion to the mitochondria. Mitochondria of bacterial origin also live inside our cells as symbionts (organisms that are in mutually beneficial relationships with other organisms). Like midichlorians, mitochondria have a number of mysterious, one might say, mystical properties, and can even exchange information, merging into branching networks. The idea of ​​the bacterial origin of mitochondria, which was proposed by Lynn Margulis in the 1970s. and was then perceived as a very controversial statement, now most biologists regard it as an established fact.
The above features of mitochondria are familiar to many from popular articles and popular culture. Some other aspects of their existence that have become clear over the past ten to twenty years are less obvious to the general public. Chief among them is apoptosis, or programmed cell death. Individual cells commit suicide for the sake of the common good - the existence of the whole organism. Around the mid-1990s. The researchers found that apoptosis is not regulated by nuclear genes, as previously thought, but by mitochondrial genes. The findings from this discovery are of great medical significance, since the inability of cells to timely apoptosis is the main cause of cancer. Now the focus of research in the field of carcinogenesis is not the nuclear genome, but the mitochondrial. But from this discovery follow much deeper conclusions. In cancer, individual cells suddenly begin to fight for “personal” freedom, throwing off the shackles of their obligations to the body as a whole. Such shackles must have been difficult to impose in the early stages of evolution of multiple-precision: why should potentially free-living cells have to sign their own death sentence for the privilege of living in a larger community of cells if they have the alternative to still live alone? It is not excluded that without programmed cell death there would never have been any connections uniting cells into a complex multicellular organism. And since programmed cell death depends on mitochondria, it is very likely that multicellular organisms could not exist without them. If this reasoning seems far-fetched to you, remember the indisputable fact that all multicellular plants and animals have mitochondria.
Another area in which mitochondria often emerge when discussing is the origin of eukaryotic cells, that is, those complex cells that make up all plants, animals, algae, and fungi. The word "eukaryotic" comes from the Greek words meaning "real core." This refers to a nucleus in which genes are localized. However, this name, to be honest, does not reflect the whole essence. In fact, the structure of eukaryotic cells, in addition to the nucleus, includes many more different elements, including, importantly, mitochondria. The evolution of such cells is the subject of heated debate. The generally accepted point of view is that they evolved gradually, step by step, until one day the primitive eukaryotic cell captures the bacterium, which after many generations of slavery has become a fully dependent mitochondria. This theory predicts that the ancestors of all eukaryotic organisms are some unknown single-celled eukaryotes without mitochondria — relics of the times when mitochondria were first “captured” and “put into action”. But now, after ten years of careful genetic analysis, it seems that all known eukaryotic cells either have mitochondria, or once had (and then lost) them. From this it follows that the origin of complex cells is inseparable from the origin of mitochondria: these two events were in fact one. If so, then mitochondria were necessary for the evolutionary origin of not only multicellular organisms, but also their components of eukaryotic cells. Thus, without mitochondria, the evolution of life on Earth would not have progressed beyond the bacterial phase.
Another aspect of the existence of mitochondria, which is less widely discussed, is associated with the difference between the two sexes or even, one may say, with the very necessity of the existence of two sexes. The question of why we need two sexes at all is a famous riddle with a famous answer. The fact is that during sexual reproduction, two parents are necessary for the birth of a child, while for vegetative or parthenogenetic reproduction only one mother is sufficient, and the father is not needed at all. Its existence is not only redundant, but also leads to an unforgivable squandering of resources. Moreover, having two sexes means that we have to choose our sexual partner from only half of the population, at least if we are looking for him to produce offspring. Both in terms of breeding and with any other, it would be much better if all people belonged to the same sex or if there were an unlimited number of sexes. Two sexes are the worst possible option. The answer to this riddle, proposed in the late 1970s, is now accepted by most scientists, but almost unfamiliar to non-specialists. As you may have guessed, it is associated with mitochondria. Two sexes are necessary because one of them must specialize in the transfer of mitochondria to offspring (in the egg cell), and the other, on the contrary, should not transmit them (in the spermatozoon). Why this should be so, we will see in Chapter 6.
Research in all these areas returned to mitochondria the attention they had been deprived of since their heyday in the 1950s, when scientists first discovered that mitochondria are cell power stations and produce almost all the energy we need. The leading scientific journal Science recognized this in 1999, when he devoted the lion's share of the next issue to mitochondria. Its cover read: "Mitochondria are returning." Mitochondria have been forgotten for two reasons. One of them was that bioenergy — the study of energy production in mitochondria — was considered a difficult and confusing area. This approach is well illustrated by an encouraging phrase, which at one time was often whispered in classrooms during lectures and reports: “Do not worry, nobody understands these mitochondrial maniacs”. The second reason is associated with the rise of molecular genetics in the second half of the 20th century. As Immo Sheffler noted, one of the outstanding “mitochondrial maniacs”, “perhaps molecular biologists did not pay attention to mitochondria because they did not immediately understand the promising conclusions and possibilities resulting from the discovery of mitochondrial genes. It took time to accumulate a fairly extensive and diverse database, allowing to proceed to address the most difficult issues of anthropology, biogenesis, medicine, evolution, and many other areas.
I have already said that mitochondria is an open secret. However, despite their newfound glory, they remain a mystery. Many serious evolutionary issues related to mitochondria are rarely raised and even less often discussed in detail even in scientific journals, and various areas of mitochondrial-related research are usually closed in their own narrow little world. I will give an example. The transport of protons through the membrane is the mechanism by which mitochondria generate energy. This mechanism is found in all life forms, including the most primitive bacteria, and is strange to the extreme. As one expert said, “for the first time after Darwin, a hypothesis that is equally paradoxical and contrary to common sense, such as, for example, the hypothesis of Einstein, Heisenberg or Schrödinger, appeared in biology.” However, this hypothesis proved to be true, and its author Peter Mitchell in 1978 received the Nobel Prize. However, few people ask the question: why, in fact, such an unusual way of energy production has become so important for various life forms? As we shall see later, the answer to this question sheds light on the very origin of life.
Another fascinating problem that has not been given due attention is the preservation of mitochondrial genes. The authors of scientific articles with the help of these genes trace our ancestry down to “mitochondrial Eve” and even reveal the kinship between different species, but rarely ask why these genes are generally preserved. They are considered the survivors of the mitochondrial bacterial past. May be. The problem is that mitochondrial genes are easily transferred en bloc1 into the nucleus. Different species in the nucleus have different mitochondrial genes, but at the same time, all species with mitochondria still retain the same basic set of mitochondrial genes. What is so special about them? As we shall see, the answer to this question will help to understand why the bacteria have never reached the level of complexity of eukaryotes. , , , , , , .
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More information about the book can be found on the publisher's website.
Table of contents
Excerpt
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From time immemorial people turned their eyes to the stars and thought about why we are here and whether we are alone in the Universe. We tend to think about why plants and animals exist, where we come from, who our ancestors were and what lies ahead. Let the answer to the main question of life, the Universe and in general not 42, as Douglas Adams once claimed, but it is no less brief and mysterious - mitochondria.They show us how life originated on our planet. They explain why bacteria reigned on it for so long and why evolution most likely did not rise above the level of bacterial mucus anywhere in the Universe. They make it possible to understand how the first complex cells arose and how earthly life climbed the stairs of ascending complexity to the heights of glory. They show us why warm-blooded creatures emerged, shaking off the shackles of the environment; why there are men and women, why we fall in love and have children. They tell us why our days in this world are numbered, why we grow old and die. They can tell us the best way to spend the sunset years of life, avoiding old age as a burden and a curse. Maybe mitochondria do not explain the meaning of life, but at least they show what it is. Is it possible to understand the meaning of life, not knowing how it works?
')
Mitochondria are small cellular organelles that produce almost all of our energy. One cell contains on average 300-400 mitochondria, that is, in the whole human body there are ten million billions of them. Mitochondria are present in virtually all complex cells. They look like bacteria, and this is the case when appearance is not deceptive. Once the mitochondria were free-living bacteria, and then - about two billion years ago - they adapted to life inside the cells. As a sign of former independence, they retained a fragment of the genome. The uneasy relationship between mitochondria and host cells defines many aspects of cell life — from energy production, the sexual process and reproduction to self-killing, aging and death.Mitochondria is one of the many “energy stations” of cells that control our lives in the most unexpected ways.
Mitochondria - an open secret. One way or another, many have heard of them. In newspaper articles and some textbooks they are called "energy stations of life." These miniature generators, hidden in cells, produce almost all the energy we need. In a single cell, there may be hundreds or thousands of mitochondria that burn organic matter with oxygen. They are so small that a billion would easily fit in a grain of sand. With the advent of mitochondria, life received a powerful engine, already operating at high speeds and ready to use. All animals, including the most sedentary, have at least some mitochondria. Even stationary plants and algae use them as a source of additional energy, an additive to the energy of photosynthesis, which they receive from their “solar panels”.
Some have probably heard the expression “mitochondrial eve”. It is assumed that she was the mother of humanity, the last common ancestor of all living people. "Mitochondrial Eve" allegedly lived in Africa (possibly 170,000 years ago), and is also called the "African Eve." We can trace our genetic ancestry to mitochondrial Eve, perhaps because mitochondria have their own small genome, which is usually passed on to the next generation only through the egg cell, and not through the sperm cell. This means that the mitochondrial genes act as a surname transmitted through the female line, which can thus be traced; so, some families raise their lineage through the male line to Wilhelm the Conqueror, Noah, or the prophet Muhammad. Recently, some of the provisions of this theory have been challenged, but in general it has withstood. Of course, this method allows not only to identify our ancestors, but also to understand who was not our ancestor. For example, analysis of mitochondrial genes suggests that the Neanderthals still did not interbreed with Homo sapiens, but were driven out to the outskirts of Europe, where they died out.
Mitochondria are also "famous" for their role in forensic medicine. They were often used to identify people, living or dead, and some such stories had a wide resonance. As in the case of the definition of our ancestors, the method of identification is based on the fact that mitochondria have their own genes. The authenticity of the remains of Nicholas II, the last Russian emperor, was confirmed by comparing his mitochondrial genes with the mitochondrial genes of his relatives. And at the end of the First World War in Berlin, a seventeen-year-old girl was pulled out of the river, who claimed that she was Anastasia, the lost daughter of Nicholas II. The girl was sent to a hospital for the mentally ill. Analysis of mitochondrial genes, conducted after her death in 1984, put an end to seventy-year disputes, showing that she was not the daughter of Nicholas II.
If we look at the recent past, the mitochondrial analysis helped to identify the bodies disfigured beyond recognition by the people who died as a result of the terrorist attack of September 11, 2001 when the towers of the World Trade Center in New York collapsed. The same method made it possible to distinguish the "real" Saddam Hussein from his many twins. One of the reasons why mitochondrial genes are so useful is the large number of copies. The genome of each mitochondria is represented by 5–10 copies, and there are usually hundreds of mitochondria in the cell, so the total number of their genomes amounts to thousands of copies. For comparison, the genome of the cell itself is represented by only two copies (which are located in the “control point” of the cell - the nucleus). Therefore, it is possible to obtain some, even minimal, number of mitochondrial genes from almost any sample. And the fact that they are common in the child, his mother and all relatives on the maternal line, makes it possible to confirm or deny the alleged relationship.
Let's go further. There is a so-called mitochondrial theory of aging. She argues that free radicals - chemically active molecules that "leak" from mitochondria in the process of normal cellular respiration, cause aging and many diseases associated with it. The problem is that “spark formation” is not completely excluded in mitochondria. When they "burn" food under the influence of oxygen, the resulting "sparks" of free radicals can damage neighboring structures, including the mitochondrial genes themselves, as well as more distant genes in the cell nucleus. Free radicals attack the genes in our cells from 10,000 to 100,000 times a day - in other words, you have to wait for some kind of trick from them literally every second. Most of the damage caused is immediately corrected, but some attacks cause irreversible mutations, that is, sustained changes in the nucleotide sequence of the gene. With age, they accumulate in the body, and the cells with the most serious injuries die. Permanent wear and is the basis of aging and related diseases. Many severe hereditary diseases are also associated with mutations resulting from the attack of free radicals on mitochondrial genes. These diseases are often inherited in a strange and unpredictable way, and their severity varies from generation to generation, but the general rule is that they all progress inexorably with age. Usually, mitochondrial diseases affect metabolically active tissues, such as muscles and the brain, and can lead to convulsions, movement disorders, blindness, deafness and muscular dystrophy.
Some have heard of mitochondria in connection with one of the methods for treating infertility, which has been fiercely controversial. Its essence is that the fragment of ooplasm containing the mitochondria from the egg of a healthy female donor is transferred to the egg of an infertile woman (the so-called transfer or transplantation of ooplasm). When information about this method was first leaked to the media, one British newspaper published an article under the catchy headline: "Infants from two mothers and one father." It cannot be said that there is no truth in this journalistic joke. Although the child receives all the “normal” genes from the “real” mother, he receives a certain number of mitochondrial genes from the female ooplasmic donor. So, strictly speaking, babies really got the genes from two different women. Despite the fact that thanks to this method, more than 30 perfectly healthy babies were born, it was subsequently banned in the UK and in the US for both ethical and practical reasons.
Mitochondria even got into the series “Star Wars” (much to the indignation of some fans) as a rather vague justification of the famous Force, which “be with you”. In the first episodes, it was assumed that this power has if not religious, then at least a spiritual nature, but in the fourth episode it was associated with the "midi-chlorians". Midichlorians, as one Jedi popularly explained, are “microscopic life forms that live in all living cells. We live with them in a mutually beneficial symbiosis. Without midichlorians there would be no life, and we would never know what Power is. ” Both in the explanation and in the title itself there is a transparent, intentional allusion to the mitochondria. Mitochondria of bacterial origin also live inside our cells as symbionts (organisms that are in mutually beneficial relationships with other organisms). Like midichlorians, mitochondria have a number of mysterious, one might say, mystical properties, and can even exchange information, merging into branching networks. The idea of ​​the bacterial origin of mitochondria, which was proposed by Lynn Margulis in the 1970s. and was then perceived as a very controversial statement, now most biologists regard it as an established fact.
The above features of mitochondria are familiar to many from popular articles and popular culture. Some other aspects of their existence that have become clear over the past ten to twenty years are less obvious to the general public. Chief among them is apoptosis, or programmed cell death. Individual cells commit suicide for the sake of the common good - the existence of the whole organism. Around the mid-1990s. The researchers found that apoptosis is not regulated by nuclear genes, as previously thought, but by mitochondrial genes. The findings from this discovery are of great medical significance, since the inability of cells to timely apoptosis is the main cause of cancer. Now the focus of research in the field of carcinogenesis is not the nuclear genome, but the mitochondrial. But from this discovery follow much deeper conclusions. In cancer, individual cells suddenly begin to fight for “personal” freedom, throwing off the shackles of their obligations to the body as a whole. Such shackles must have been difficult to impose in the early stages of evolution of multiple-precision: why should potentially free-living cells have to sign their own death sentence for the privilege of living in a larger community of cells if they have the alternative to still live alone? It is not excluded that without programmed cell death there would never have been any connections uniting cells into a complex multicellular organism. And since programmed cell death depends on mitochondria, it is very likely that multicellular organisms could not exist without them. If this reasoning seems far-fetched to you, remember the indisputable fact that all multicellular plants and animals have mitochondria.
Another area in which mitochondria often emerge when discussing is the origin of eukaryotic cells, that is, those complex cells that make up all plants, animals, algae, and fungi. The word "eukaryotic" comes from the Greek words meaning "real core." This refers to a nucleus in which genes are localized. However, this name, to be honest, does not reflect the whole essence. In fact, the structure of eukaryotic cells, in addition to the nucleus, includes many more different elements, including, importantly, mitochondria. The evolution of such cells is the subject of heated debate. The generally accepted point of view is that they evolved gradually, step by step, until one day the primitive eukaryotic cell captures the bacterium, which after many generations of slavery has become a fully dependent mitochondria. This theory predicts that the ancestors of all eukaryotic organisms are some unknown single-celled eukaryotes without mitochondria — relics of the times when mitochondria were first “captured” and “put into action”. But now, after ten years of careful genetic analysis, it seems that all known eukaryotic cells either have mitochondria, or once had (and then lost) them. From this it follows that the origin of complex cells is inseparable from the origin of mitochondria: these two events were in fact one. If so, then mitochondria were necessary for the evolutionary origin of not only multicellular organisms, but also their components of eukaryotic cells. Thus, without mitochondria, the evolution of life on Earth would not have progressed beyond the bacterial phase.
Another aspect of the existence of mitochondria, which is less widely discussed, is associated with the difference between the two sexes or even, one may say, with the very necessity of the existence of two sexes. The question of why we need two sexes at all is a famous riddle with a famous answer. The fact is that during sexual reproduction, two parents are necessary for the birth of a child, while for vegetative or parthenogenetic reproduction only one mother is sufficient, and the father is not needed at all. Its existence is not only redundant, but also leads to an unforgivable squandering of resources. Moreover, having two sexes means that we have to choose our sexual partner from only half of the population, at least if we are looking for him to produce offspring. Both in terms of breeding and with any other, it would be much better if all people belonged to the same sex or if there were an unlimited number of sexes. Two sexes are the worst possible option. The answer to this riddle, proposed in the late 1970s, is now accepted by most scientists, but almost unfamiliar to non-specialists. As you may have guessed, it is associated with mitochondria. Two sexes are necessary because one of them must specialize in the transfer of mitochondria to offspring (in the egg cell), and the other, on the contrary, should not transmit them (in the spermatozoon). Why this should be so, we will see in Chapter 6.
Research in all these areas returned to mitochondria the attention they had been deprived of since their heyday in the 1950s, when scientists first discovered that mitochondria are cell power stations and produce almost all the energy we need. The leading scientific journal Science recognized this in 1999, when he devoted the lion's share of the next issue to mitochondria. Its cover read: "Mitochondria are returning." Mitochondria have been forgotten for two reasons. One of them was that bioenergy — the study of energy production in mitochondria — was considered a difficult and confusing area. This approach is well illustrated by an encouraging phrase, which at one time was often whispered in classrooms during lectures and reports: “Do not worry, nobody understands these mitochondrial maniacs”. The second reason is associated with the rise of molecular genetics in the second half of the 20th century. As Immo Sheffler noted, one of the outstanding “mitochondrial maniacs”, “perhaps molecular biologists did not pay attention to mitochondria because they did not immediately understand the promising conclusions and possibilities resulting from the discovery of mitochondrial genes. It took time to accumulate a fairly extensive and diverse database, allowing to proceed to address the most difficult issues of anthropology, biogenesis, medicine, evolution, and many other areas.
I have already said that mitochondria is an open secret. However, despite their newfound glory, they remain a mystery. Many serious evolutionary issues related to mitochondria are rarely raised and even less often discussed in detail even in scientific journals, and various areas of mitochondrial-related research are usually closed in their own narrow little world. I will give an example. The transport of protons through the membrane is the mechanism by which mitochondria generate energy. This mechanism is found in all life forms, including the most primitive bacteria, and is strange to the extreme. As one expert said, “for the first time after Darwin, a hypothesis that is equally paradoxical and contrary to common sense, such as, for example, the hypothesis of Einstein, Heisenberg or Schrödinger, appeared in biology.” However, this hypothesis proved to be true, and its author Peter Mitchell in 1978 received the Nobel Prize. However, few people ask the question: why, in fact, such an unusual way of energy production has become so important for various life forms? As we shall see later, the answer to this question sheds light on the very origin of life.
Another fascinating problem that has not been given due attention is the preservation of mitochondrial genes. The authors of scientific articles with the help of these genes trace our ancestry down to “mitochondrial Eve” and even reveal the kinship between different species, but rarely ask why these genes are generally preserved. They are considered the survivors of the mitochondrial bacterial past. May be. The problem is that mitochondrial genes are easily transferred en bloc1 into the nucleus. Different species in the nucleus have different mitochondrial genes, but at the same time, all species with mitochondria still retain the same basic set of mitochondrial genes. What is so special about them? As we shall see, the answer to this question will help to understand why the bacteria have never reached the level of complexity of eukaryotes. , , , , , , .
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