Holistic medicine

Evolution: theories, meanings and examples


Book review: “Evolution in four dimensions” by Eva Jablonka and Marion J. Lamb
Nature accompanies our thinking. Followers of naturopathy often equate nature with gentle or romanticize it as a counterpoint to alienation or the side effects of "unnatural" methods of medical treatment. Often there is a lack of basic knowledge about natural relationships, especially how the evolution of life forms works. Instead, some “natural healers” use pre-scientific ideas with which people before the Darwinian revolution tried to explain the events of life.

Jablonka and Lamb criticize synthetic evolution theory, the standard of evolutionary science. They consider it necessary to expand it. Molecular, developmental and behavioral biology today showed that inheritance also takes place outside of genes and DNA.

Presentation of the authors

“You should see everything as simply as possible - but not easier either,” quote Eva Jablonka and Marion J. Lamb Albert Einstein and give with their work “Evolution in four dimensions. How genetics, epigenetics, behavior and symbols shape the history of life ”is an example of this claim. This is because they give a new impetus to inheritance in living beings without slipping into scientific jargon on the one hand, without understanding the outsider and on the other hand without shortening it so that the information becomes wrong.

Eva Jablonka, born in Poland in 1952, works as a biologist, evolution theorist and geneticist in Israel and researches non-genetic inheritance of animal behavior as a professor at the Cohn Institute for the History of Science and Philosophy of Science at the University of Tel Aviv. Marion J. Lamb taught at Birkbeck College, University of London and has been researching epigenetic inheritance with Eva Jablonka for several decades.

The English-language original is already 12 years old and is now finally available in German translation from Hirzel-Verlag.

A tough scientific chunk

The evolutionary sciences are extremely complex, and the history of science of the theories of evolution has been controversial since Darwin. In addition, biology is constantly gathering new insights into the way genes work.

The American biologists Jablonka and Lamb concentrate on a "development and system-oriented approach to inheritance and revolution" and deal with concepts that include development-induced hereditary epigenetic changes as the origin of new variants, which pure geneticists denied.

"Evolution in four dimensions" deals with a tough scientific chunk. However, this is of great importance for medicine: Knowing how inheritance works has a direct impact on assessing genetic dispositions for diseases and using the logical methods to treat them.

In order to convey the matter in an understandable manner, each chapter ends with a fictional dialogue in which the authors answer the critical questions of an Advoctus Diaboli.

Popular science

“Evolution in four dimensions” is specifically aimed at laypersons. The first part in particular may therefore be boring for academically trained biologists, since the authors of Darwin, Lamarck and Weismann describe in detail and repeat what has been written. So that laypeople first understand what it is all about, these repetitions are literally understandable.

They may even be necessary, because the second part deals with an expanded concept of evolution that includes the passing on of information such as behavior, symbols, writing and language. Without fully explaining what inheritance made possible with Darwin, Lamarck, Weismann, in modern synthesis, molecular biology, with Richard Dawkins and Stephen Jay Gould, non-specialist readers will hardly understand what the authors of the Criticize fixation on the gene as a carrier of inheritance.

According to Lamb and Jablonka, humans control their evolution through language and culture, which became at least as important as genetic selection.

How does inheritance work?

The book is about inheritance, and the authors focus on four theses:

1) Biological inheritance is more than just genes

2) Some hereditary variations do not arise purely by accident.

3) Some forms of information acquired are hereditary.

4) The change of species is not only the result of selection, but also of learning.

In doing so, they contradict the traditional Darwinian view that adaptation is always the result of natural selection of random genetic variants. Her theses are based on experimental and empirical findings which, according to Jablonka and Lamb, make a new concept of inheritance necessary.

Not just the genes?

Not only genes control inheritance, but according to the authors, heredity has three further dimensions: Molecular biology would have shown that body cells pass on information to daughter cells through epigenetic distribution. Animals would pass on information through specific behaviors, i.e. they have another inheritance system - social learning. With symbol-based inheritance, people even had a third inheritance system, for example through language and writing. So language would have played a crucial role in human evolution.

Not only genetic, but also epigenetic processes, behavior and symbol-based inheritance would produce additional variants from which natural evolution can choose. Environmental skills acquired also played an essential role in evolutionary processes. Instead of seeing the genes alone as the originator of the inheritance, the authors choose a four-dimensional perspective, as the title of the book suggests.

The first part of the extensive work deals with the genetic system. Its first chapter outlines Charles Darwin's theory and shows why its development in the 20th century focused on genes. Chapter 2 shows how molecular biology broke this focus, and Chapter 3 discusses that not all mutations are the result of random events.

Three other dimensions of inheritance

The second part deals with the three further dimensions of inheritance, first the epigenetic inheritance systems such as architectural memory, i.e. the inheritance of structures or the memory of the chromosomes, and the transmission of epigenetic variations to the offspring.

This is followed in Chapter 5 by behavior-specific inheritance systems such as the passing on of information through social learning, the inheritance through the passing on of behavior-influencing substances or the inheritance through non-imitative social learning such as opening milk bottles, learning through imitation, for example, of singing whales and learning through traditions and cumulative evolution.

The sixth chapter deals with symbol systems of inheritance. This includes symbolically mediated communication as an inheritance system, cultural evolution and communication through symbols, the "selfish meme", evolutionary psychology, the reading and writing module and ultimately the transition from evolution to history.

Synthesis between genetic and non-genetic inheritance

In the third part, the authors put the parts together again as a whole. In Chapter 7, they examine the interactions between genes and epigenetic inheritance systems. How do epigenetic systems influence the generation of genetic variability? How do genomic imprints and gene selection affect? What does genetic assimilation mean?

Chapter 8 outlines genes and behavior as well as genes and language. This includes genes, learning and instincts as well as cultural niche construction. The authors address the question: What is language? And explain how language changed genes.

Chapter 9 is called "Lamarck Mechanisms: The Evolution of the" Justified Presumption ". Here Jablonka and Lamb show the origin and genetics of interpretive mutations such as the origin of epigenetic inheritance systems. It goes on to inheritance, RNA interference and the origins of tradition in animals. The authors investigate: Under what conditions does communication evolve through symbols?

Darwin's idea of ​​inheritance

So it is a complex matter that the two biologists are trying to explain as clearly as possible. First of all, they show that there is no “undisputed, scientifically accepted evolutionary theory that every biologist understands in the same way”. In doing so, they do not support the pseudoscience of intelligent design, which puts the Christian belief in creation in modern terms, but rather show the complexity of the theories within evolutionary science.

You ask: Can natural selection alone explain any form of evolutionary change? Where do they come from, how do all these hereditary variants arise, from which the selection should choose?

According to the authors, Darwin himself did not provide an adequate answer to these questions. According to him, the decisive laws of life were reproduction (reproduction), inheritance, the differences between individuals and the struggle for existence.

Darwin's concept is also possible without genes

The authors criticize this Darwinian concept as extremely general; it says nothing about the processes of inheritance and reproduction, "nothing about how hereditary variation arises, nor about the nature of the entity that is supposed to change with time through natural entities." According to Jablonka and Lamb, it would be possible to be a consistent Darwinist without simultaneously following Mendel's laws, mutating genes and DNA codes.

According to the authors, Darwin suspected hereditary variability on the one hand through direct effects of the environment on the organism, and on the other hand an indirect mechanism through “use and non-use of organs”.

Darwin was not far from Lamarck in the idea that acquired traits can be inherited, and "practically all biologists at the beginning of the 19th century" shared this view. Darwin and his followers would have been aware that a viable inheritance theory was missing.

It was the neo-Darwinist Weismann who, according to the authors, refused to inherit acquired traits since the 1880s. In contrast to Darwin, he excluded an evolutionary effect from the use or non-use of organs. The sexual processes caused the hereditary differences between the individuals, according to Weismann.

Modern synthesis

In the 1930s there was a modern synthesis of Darwinian and Weismannian ideas. This was based on the following requirements:

1) Inheritance occurs through the transmission of germ cell genes

2) Hereditary variations are the result of random combinations of alleles that are generated in the course of different sexual processes.

3) Selection takes place between individuals.

There was contradiction to these theses within evolutionary biology. Many biologists have criticized the fact that inheritance involves more than passing on nuclear genes from one generation to another. The egg cell would also have an important role in the development of species characteristics.

Molecular Neo-Darwinism since the 1950s ultimately focused on DNA that Darwin knew nothing about. Molecular genetic studies would have shown, however, that populations showed considerably more hereditary variability than expected. Biochemical findings in the 1960s showed that chance had a significant impact on how natural populations developed.

Richard Dawkins and Stephen Jay Gould

Richard Dawkins finally explained that an individual's body is a vehicle, not a replicator. According to Dawkins, individual adjustments would have no effect on inheritance.

The American paleontologist Stephen Jay Gould criticized Dawkins sharply. He said that any gene-centered view of evolution must inevitably be misleading. Because individuals, groups or species always survived - not the genes. Instead, according to Gould, one has to consider geological events as well as coincidences that influenced the genetic variants in populations - natural selection is only one of many factors in the world of living things.

This controversy continued until Gould's death in 2002. According to the authors, the polemic with which the two camps fought concealed the fact that Gould and Dawkins had two opinions on inheritance: on the one hand, both considered genes as the only essential inheritance units in living beings (except humans) and second, acquired traits as non-hereditary.

Mutations of individual genes irrelevant

According to the authors, individual mutations are statistically neutral, only when interacting with other genes and under certain environmental conditions does the likelihood of producing offspring increase - if the environmental conditions and interactions with genes are different, the same mutation can have a disadvantage. In this respect, evolutionary change as a result of individual mutations is untenable. Rather, units of evolutionary change are networks and not individual genes.

Can an inheritance system be replaced?

In Chapter III of the first part, Jablonka and Lamb discuss that the genetic inheritance system cannot be replaced by other forms of inheritance, although this is possible in theory. The various epigenetic inheritance systems have in common that they transmit information from cell to cell.

Epigenetically inherited does not necessarily mean “good”. Cancer cells, for example, multiplied and spread in the tissues, thereby damaging the organism. An epigenetic variant, on the other hand, has to bring advantages at the overall organic level so that it spreads in a population.

The same applies to epigenetic inheritance. "In a multicellular organism, each type of variability is often limited - each individual variant first has to go through the bottleneck of development before a viable organism emerges from it."

Social issues

Lamb and Jablonka write: "Since many biologists emphasize the genetic aspect in human behavior, laypeople often conclude from this that general behaviors (especially reprehensible ones) are" genetically determined ", thus" natural "and (...) inevitable. This is nonsense (…)."

People, on the other hand, have a story, could plan their future and create shared imaginary worlds. In contrast, genes have neither responsibility nor explanatory power. Sociobiologists sometimes conduct “scientific” soft pornography and might perhaps satisfy the desire for simple causal thinking - without significant empirical evidence.

Genes, as a “connection to our distant past”, have something that touches us in an irrational-mystical way; the evolutionary history of many human sociobiologists is based on this strange combination of romance and science.

New perspectives

The authors state: "What we call" a plant "or" an animal "is actually an integrated community of species that live together, develop and evolve together." Systems biology is today from an idea to the mainstream within Become biology. Their primary focus would be on the cell networks. Science historians of the future might decide whether their approach is a decisive change of perspective in evolutionary thinking.

Medical consequences

If, as the authors suspect, individual experiences have an impact on the offspring, i.e. genetic and non-genetic inheritance interact, this has consequences, as Jablonka and Lamb use examples to explain. They describe how, in northern Sweden, a grandfather's childhood access to food influenced his grandchildren's mortality risk, and how grandmother's food supply affected granddaughters' mortality.

An English study from the 1990s would have shown that the sons of smokers earlier than adults were at higher risk of developing obesity.

In both men and women, non-genetic factors would have an impact on their offspring. Any behavior learned in the long term would have an epigenetic effect on inheritance.

You quote Lawrence Parson: "The brain is a cultural artifact, it not only constructs, but also reflects culture."

For the treatment of diseases that have a genetic component, Lamb and Jablonka's approach means that there is not one gene that decides whether an illness breaks out or not, and the average increased risk in such a genetic predisposition says nothing about the individual case.

A treatment that makes sense for a person affected can even be harmful for another person affected by this genetic peculiarity - it is not a question of the individual gene, but of networks of different genes, which in turn interact with non-genetic factors.

The authors discuss as biologists who deal with fundamental questions of evolutionary science, not as medical professionals.

However, their emphasis on epigenetic structures and the move away from "gene determinism" raises essential questions for diseases with a strong genetic component, from autism and Alzheimer's to some types of cancer to schizophrenia: social and cultural experiences in the family influence here the " genetic disposition ”. These diseases can only be prevented if genetic, epigenetic and symbolic-cultural aspects are taken into account.

If you are interested in naturopathy and would like to find out what nature, genes, DNA or inheritance are, this book is recommended as a basis and can be read more fluently than other standard works on evolutionary science. (Dr. Utz Anhalt)

Author and source information

This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.

Dr. phil. Utz Anhalt, Barbara Schindewolf-Lensch

Swell:

  • Jablonka, Eva; Lamb, Marion J .: Evolution in four dimensions: How genetics, epigenetics, behavior and symbols shape the history of life, Hirzel, S., Verlag, 2017


Video: Darwin and Natural Selection: Crash Course History of Science #22 (December 2021).