Sep 3, 2021 09:05 PM
The ‘selfish gene’ persists for the reason all good scientific metaphors do: it remains a sharp tool for clear thinking
https://aeon.co/essays/why-the-selfish-g...nking-tool
EXCERPTS: In the decades following that bet, The Selfish Gene has come to play a unique role in evolutionary biology, simultaneously influential and contentious. At the heart of the disagreements lay the book’s advocacy of what has become known as the gene’s-eye view of evolution. To its supporters, the gene’s-eye view presents an unrivalled introduction to the logic of natural selection. To its critics, ‘selfish genes’ is a dated metaphor that paints a simplistic picture of evolution while failing to incorporate recent empirical findings. To me, it is one of biology’s most powerful thinking tools. However, as with all tools, in order to make the most of it, you must understand what it was designed to do.
[...] Under the framework of population genetics, evolution is captured by mathematically describing the increase and decrease of alleles in a population over time.
The gene’s-eye view took this a step further, to argue that biologists are always better off thinking about evolution and natural selection in terms of genes rather than organisms. This is because organisms lack the evolutionary longevity required to be the central unit in evolutionary explanations. They are too temporary on an evolutionary timescale, a unique combination of genes and environment – here in this generation but gone in the next. Genes, in contrast, pass on their structure intact from one generation to the next, ignoring mutation and recombination. Therefore, only they possess the required evolutionary longevity. Traits that you can see, the argument goes, such as the particular fur of a polar bear or the flower of an orchid (known as a phenotype), are not for the good of the organism, but of the genes. The genes, and not the organism, are the ultimate beneficiaries of natural selection.
This approach has also been called selfish-gene thinking, because natural selection is conceptualised as a struggle between genes, typically through how they affect the fitness of the organism in which they reside, for transmission to the next generation...
[...] In this telling, evolution is the process by which immortal selfish genes housed in transient organisms struggle for representation in future generations. ... Dawkins argued that evolution involves two entities: replicators and vehicles, playing complementary roles. Replicators are those entities that copies are made of and that are transmitted faithfully from one generation to the next; in practice, this usually means genes. The second entity, vehicles, are where replicators are bundled together: this is the entity that actually comes into contact with the external environment and interacts with it. The most common kind of vehicle is the organism, such as an animal or a plant, though it can also be a cell, as in the case of cancer.
[...] This perspective is especially valuable when looking at phenomena that seem to have little benefit to individuals. Why would the sterile worker bee lay down her life in service of the colony queen? The question is a conundrum from the perspective of the individual bee, but less so from that of her genes.
[...] The gene’s-eye view also sheds light on the phenomenon of genomic conflict. These are situations when what helps one gene improve its chances of being transmitted to the next generation reduces another gene’s chances. Genomic conflicts often arise because not all genes are transmitted in the same way. Consider the case of male sterility in hermaphroditic plants. Plants carry their genetic material in more than one location. The first is the nuclear genome, where the absolute majority of genes are located. Here, half of the genes come from the mother and half from the father. The next is the mitochondrial genome. In contrast to the nuclear genome, all the genetic material in the mitochondria come from the mother.
All hermaphroditic plants face a trade-off between investing in pollen (male reproduction) or ovules (female reproduction). This is the dilemma faced by nuclear genes. For mitochondrial genes, however, the answer is easy. Because of their maternal inheritance, their only way to the next generation is through the ovules. This has resulted in mitochondrial mutations that knock out pollen production, effectively turning the plant female. When this happens, the population consists of hermaphrodites and females, and the only way that females can reproduce is if their ovules are fertilised by pollen from the hermaphrodites. This greatly reduces their chances of reproduction. But the flip side, for the mitochondrial genes, is that, every time reproduction happens, they are guaranteed to be transmitted. In response, several nuclear genes have evolved the ability to restore male reproduction, sometimes resulting in an evolutionary arms race between mitochondrial male sterility genes and nuclear restorer genes.
[...] The popularity of the selfish gene idea has provided a tempting launchpad for bashing contemporary evolutionary theory. [...] ‘There is always fame to be won in science by killing the king,’ as John Maynard Smith put it in 1988.
A big complaint is that the selfish-gene concept is too attached to ideas of the past. Critics associate it with the so-called ‘modern synthesis’: an integration of findings in botany, systematics, cytology, palaeontology and ecology into a cohesive theory of evolution, culminating in the formation of the Society for the Study of Evolution 75 years ago. The association between the gene’s-eye view and the modern synthesis is not undeserved – both Williams and Dawkins repeatedly emphasised that the selfish genes metaphor was nothing but a modern expression of the classic theory.
Papers and books challenging the modern synthesis started to be published soon after its completion. [...] All these things, of course, are interesting and worthy of study. But calls to kill the king reveal something deeper that goes beyond disagreements over interpretations of empirical data or preferences for different mathematical models. It is also about how we should think and talk about evolution.
[...] To me, the gene’s-eye view has offered all the drama I need. More practically, the gene’s-eye view has persisted for the same reason all good metaphors do, because it aids our thinking as we take on the complexities of the living world. It helps us structure our thoughts and it prompts us to address questions that can be answered empirically. At their best, metaphors have many things in common with mathematical models in that they help to isolate and examine certain properties of a biological observation.
At their worst, they make us dismiss other things. [...] We should always worry not only about what questions a metaphor makes us ask, but also what questions go unasked. That being said, biology is difficult, and we need all the help we can get. When properly understood, the gene’s-eye view offers some of the best help there is... (MORE - missing details)
https://aeon.co/essays/why-the-selfish-g...nking-tool
EXCERPTS: In the decades following that bet, The Selfish Gene has come to play a unique role in evolutionary biology, simultaneously influential and contentious. At the heart of the disagreements lay the book’s advocacy of what has become known as the gene’s-eye view of evolution. To its supporters, the gene’s-eye view presents an unrivalled introduction to the logic of natural selection. To its critics, ‘selfish genes’ is a dated metaphor that paints a simplistic picture of evolution while failing to incorporate recent empirical findings. To me, it is one of biology’s most powerful thinking tools. However, as with all tools, in order to make the most of it, you must understand what it was designed to do.
[...] Under the framework of population genetics, evolution is captured by mathematically describing the increase and decrease of alleles in a population over time.
The gene’s-eye view took this a step further, to argue that biologists are always better off thinking about evolution and natural selection in terms of genes rather than organisms. This is because organisms lack the evolutionary longevity required to be the central unit in evolutionary explanations. They are too temporary on an evolutionary timescale, a unique combination of genes and environment – here in this generation but gone in the next. Genes, in contrast, pass on their structure intact from one generation to the next, ignoring mutation and recombination. Therefore, only they possess the required evolutionary longevity. Traits that you can see, the argument goes, such as the particular fur of a polar bear or the flower of an orchid (known as a phenotype), are not for the good of the organism, but of the genes. The genes, and not the organism, are the ultimate beneficiaries of natural selection.
This approach has also been called selfish-gene thinking, because natural selection is conceptualised as a struggle between genes, typically through how they affect the fitness of the organism in which they reside, for transmission to the next generation...
[...] In this telling, evolution is the process by which immortal selfish genes housed in transient organisms struggle for representation in future generations. ... Dawkins argued that evolution involves two entities: replicators and vehicles, playing complementary roles. Replicators are those entities that copies are made of and that are transmitted faithfully from one generation to the next; in practice, this usually means genes. The second entity, vehicles, are where replicators are bundled together: this is the entity that actually comes into contact with the external environment and interacts with it. The most common kind of vehicle is the organism, such as an animal or a plant, though it can also be a cell, as in the case of cancer.
[...] This perspective is especially valuable when looking at phenomena that seem to have little benefit to individuals. Why would the sterile worker bee lay down her life in service of the colony queen? The question is a conundrum from the perspective of the individual bee, but less so from that of her genes.
[...] The gene’s-eye view also sheds light on the phenomenon of genomic conflict. These are situations when what helps one gene improve its chances of being transmitted to the next generation reduces another gene’s chances. Genomic conflicts often arise because not all genes are transmitted in the same way. Consider the case of male sterility in hermaphroditic plants. Plants carry their genetic material in more than one location. The first is the nuclear genome, where the absolute majority of genes are located. Here, half of the genes come from the mother and half from the father. The next is the mitochondrial genome. In contrast to the nuclear genome, all the genetic material in the mitochondria come from the mother.
All hermaphroditic plants face a trade-off between investing in pollen (male reproduction) or ovules (female reproduction). This is the dilemma faced by nuclear genes. For mitochondrial genes, however, the answer is easy. Because of their maternal inheritance, their only way to the next generation is through the ovules. This has resulted in mitochondrial mutations that knock out pollen production, effectively turning the plant female. When this happens, the population consists of hermaphrodites and females, and the only way that females can reproduce is if their ovules are fertilised by pollen from the hermaphrodites. This greatly reduces their chances of reproduction. But the flip side, for the mitochondrial genes, is that, every time reproduction happens, they are guaranteed to be transmitted. In response, several nuclear genes have evolved the ability to restore male reproduction, sometimes resulting in an evolutionary arms race between mitochondrial male sterility genes and nuclear restorer genes.
[...] The popularity of the selfish gene idea has provided a tempting launchpad for bashing contemporary evolutionary theory. [...] ‘There is always fame to be won in science by killing the king,’ as John Maynard Smith put it in 1988.
A big complaint is that the selfish-gene concept is too attached to ideas of the past. Critics associate it with the so-called ‘modern synthesis’: an integration of findings in botany, systematics, cytology, palaeontology and ecology into a cohesive theory of evolution, culminating in the formation of the Society for the Study of Evolution 75 years ago. The association between the gene’s-eye view and the modern synthesis is not undeserved – both Williams and Dawkins repeatedly emphasised that the selfish genes metaphor was nothing but a modern expression of the classic theory.
Papers and books challenging the modern synthesis started to be published soon after its completion. [...] All these things, of course, are interesting and worthy of study. But calls to kill the king reveal something deeper that goes beyond disagreements over interpretations of empirical data or preferences for different mathematical models. It is also about how we should think and talk about evolution.
[...] To me, the gene’s-eye view has offered all the drama I need. More practically, the gene’s-eye view has persisted for the same reason all good metaphors do, because it aids our thinking as we take on the complexities of the living world. It helps us structure our thoughts and it prompts us to address questions that can be answered empirically. At their best, metaphors have many things in common with mathematical models in that they help to isolate and examine certain properties of a biological observation.
At their worst, they make us dismiss other things. [...] We should always worry not only about what questions a metaphor makes us ask, but also what questions go unasked. That being said, biology is difficult, and we need all the help we can get. When properly understood, the gene’s-eye view offers some of the best help there is... (MORE - missing details)