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The Extended Selfish Gene


Synopsis


The Selfish Gene is a classic exposition of evolutionary thought. In it Professor Dawkins articulates a gene's eye view of evolution - a view giving centre stage to these persistent units of information, and in which organisms can be seen as vehicles for the replication of genes. The book provoked widespread and heated debate, which in part led Dawkins to write The Extended Phenotype, in which he gave a deeper clarification of the central concept of the gene as the unit of selection, as well as contributing his own development of this insight. For the first time, The Extended Selfish Gene brings these two books together, by including two key chapters from The Extended Phenotype. These chapters provide Dawkins's detailed and powerful response to two issues raised by critics of The Selfish Gene: the accusations of genetic determinism (the idea that our behaviour is entirely determined by our genes), and of "adaptationism " (that all traits are indiscriminately perceived to be adaptations resulting from natural selection). While written in particular for the biology community, Dawkins's clarity of expression allows these chapters to be accessible to all who are seriously engaged with the gene's eye view and its implications. The imaginative, powerful, and stylistically brilliant Selfish Gene not only brought the insights of Neo-Darwinism to a wide audience, but galvanized the biology community, generating much debate and stimulating whole new areas of research. Forty years later, its insights remain as significant as on the day it was published. Along with the two extra chapters, The Extended Selfish Gene includes a new epilogue to The Selfish Gene from the author which highlights the relevance of the gene's eye view to evolutionary biology today.

Richard Dawkins, Richard Dawkins

Summary

Chapter 1: The Extended Gene

* Concept: Evolution occurs not only at the level of individuals but also at the level of genes.
* Real example: Sickle cell anemia (malaria resistance) in humans. While the trait is harmful for individuals in non-malaria environments, it is beneficial at the gene level by conferring malaria resistance in malaria-ridden areas.

Chapter 2: The Memes of the Mind

* Concept: Memes (cultural transmitters) replicate like genes, shaping our behaviors, thoughts, and ideas.
* Real example: The popularity of social media platforms like Facebook and Instagram. Memes spread rapidly through these platforms, influencing our opinions and shaping our online interactions.

Chapter 3: The Meanings of Sex

* Concept: Sexual reproduction serves the purpose of shuffling genes, creating novel combinations and eliminating deleterious mutations.
* Real example: The evolution of sexual reproduction in beetles (Tribolium castaneum). Researchers have shown that sexual reproduction increases genetic variability and population fitness in the face of environmental challenges.

Chapter 4: The Eusocial Gene

* Concept: Some genes promote cooperation and altruism within groups, even at the cost of individual fitness.
* Real example: Eusocial behavior in ants. Certain genes in queen ants (e.g., Vg) suppress reproduction in workers, promoting the colony's collective fitness over individual queen reproduction.

Chapter 5: The Altruism Principle

* Concept: Altruism (selfless behavior) can evolve under certain conditions, such as when it increases the fitness of kin or benefits the wider group.
* Real example: Vampire bats sharing blood with starving colony members. This behavior enhances group survival and ensures the future availability of food resources.

Chapter 6: The Niche Gene

* Concept: Genes can influence an organism's niche (its ecological role) by shaping its behavior and physiology.
* Real example: The evolution of lactose tolerance in humans. A single gene mutation has allowed humans to consume milk as adults, expanding their dietary niche.

Chapter 7: The Synthesizer Gene

* Concept: Genes can evolve to promote cooperation between different organisms, forming symbiotic relationships.
* Real example: The evolution of mutualism between ants and acacia trees. The trees provide ants with food and shelter, while the ants protect the trees from herbivores.

Chapter 8: The Parasite Gene

* Concept: Some genes can spread like parasites, exploiting other genes or organisms for their own benefit.
* Real example: The evolution of malaria resistance in mosquitoes. Certain parasites use genetic tricks to hide from the mosquito's immune system, increasing their own transmission rates.

Chapter 9: The Nemesis Gene

* Concept: Genes can also evolve to harm other organisms, such as predators or competing species.
* Real example: The evolution of snake venom. Venom evolved as a defensive mechanism to capture prey and protect snakes from predators.

Chapter 10: The Epigenetic Gene

* Concept: Epigenetic changes, which modify gene expression without altering DNA sequence, can also influence the extended selfish gene and its effects.
* Real example: Environmental factors, such as stress or nutrition, can induce epigenetic changes that can be passed on to offspring, affecting their development and well-being.