Marion J. Lamb
Encyclopedia
Marion J. Lamb was Senior Lecturer at Birkbeck, University of London
, before her retirement. She studied the effect of environmental conditions such as heat, radiation and pollution on metabolic
activity and genetic mutability in the fruit fly Drosophila
. From the late 1980s, Lamb collaborated with Eva Jablonka
, researching and writing on the inheritance of epigenetic
variations, and in 2005 they co-authored the book Evolution in Four Dimensions, considered by some to be in the vanguard of an ongoing revolution within evolutionary biology.
Building on the approach of evolutionary developmental biology
, and recent findings of molecular
and behavioral biology, they argue the case for the transmission of not just genes per se, but heritable variations transmitted from generation to generation by whatever means. They suggest that such variation can occur at four levels. Firstly, at the established physical level of genetics. Secondly, at the epigenetic level involving variation in the “meaning” of given DNA strands, in which variations in DNA translation during developmental processes are subsequently transmitted during reproduction, which can then feed back into sequence modification of DNA itself.
These epigenetic changes - chemical modifications and markers that change the way enzymes and regulatory proteins have access to DNA - are currently being studied to explain many non-Mendelian patterns of inheritance. The best understood mechanism is nucleotide methylation
that silences a gene. Methylation can be inherited during cell division, both asexually (mitotic) during development and wound healing, but in some instances also sexually (meiotic). Methylation is linked in some instances to RNA interference, the new and emerging science of RNA regulation of gene expression.
The third dimension comprises the transmission of behavioural traditions. There are for example documented cases of food preferences being passed on, by social learning, in several animal species, which remain stable from generation to generation while conditions permit. The fourth dimension is symbolic inheritance, which is unique to humans, and in which traditions are passed on “through our capacity for language, and culture, our representations of how to behave, communicated by speech and writing.”
In their treatment of the higher levels, Jablonka and Lamb distinguish their approach from the banalities of evolutionary psychology, of "memes", and even from Chomskyian ideas of universal grammar. They argue that there are constant interactions between the levels - epigenetic, behavioural and even symbolic inheritance mechanisms also produce selection pressures on DNA-based inheritance and can, in some cases, even help direct DNA changes themselves - so "evolving evolution". To liven their text, they utilise thought experiments and dialogue with a sceptical enquirer, one IM-Ifcha Mistraba, Aramaic, they say, for "the opposite conjecture".
Since publication of this book, Lamb and Jablonka have responded to critics, citing evidence which affirms their view that evolutionary change is facilitated by all types of hereditary information that they have identified: genetic, epigenetic, behavioural and cultural. They claim that their approach broadens the definitions of terms such as ‘units of heredity’, ‘units of evolution’, and ‘units of selection’, and they maintain that ‘information’ can be a useful concept if it is defined in terms of its effects on the receiver. They concede that evolutionary theory is not undergoing a paradigm shift or Kuhnian revolution, but argue that the incorporation of new data and ideas about hereditary variation, and the role of development in generating it, is leading to a very different version of Darwinism than the gene-centred one which has dominated evolutionary thinking in the second half of the twentieth century.
(First published 1990).
Birkbeck, University of London
Birkbeck, University of London is a public research university located in London, United Kingdom and a constituent college of the federal University of London. It offers many Master's and Bachelor's degree programmes that can be studied either part-time or full-time, though nearly all teaching is...
, before her retirement. She studied the effect of environmental conditions such as heat, radiation and pollution on metabolic
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...
activity and genetic mutability in the fruit fly Drosophila
Drosophila
Drosophila is a genus of small flies, belonging to the family Drosophilidae, whose members are often called "fruit flies" or more appropriately pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit...
. From the late 1980s, Lamb collaborated with Eva Jablonka
Eva Jablonka
Eva Jablonka is a theorist and geneticist, known especially for her interest in epigenetic inheritance. Born in 1952 in Poland, she emigrated to Israel in 1957. She is a professor at the Cohn Institute for the History of Philosophy of Science and Ideas at Tel Aviv University...
, researching and writing on the inheritance of epigenetic
Epigenetics
In biology, and specifically genetics, epigenetics is the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence – hence the name epi- -genetics...
variations, and in 2005 they co-authored the book Evolution in Four Dimensions, considered by some to be in the vanguard of an ongoing revolution within evolutionary biology.
Building on the approach of evolutionary developmental biology
Evolutionary developmental biology
Evolutionary developmental biology is a field of biology that compares the developmental processes of different organisms to determine the ancestral relationship between them, and to discover how developmental processes evolved...
, and recent findings of molecular
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...
and behavioral biology, they argue the case for the transmission of not just genes per se, but heritable variations transmitted from generation to generation by whatever means. They suggest that such variation can occur at four levels. Firstly, at the established physical level of genetics. Secondly, at the epigenetic level involving variation in the “meaning” of given DNA strands, in which variations in DNA translation during developmental processes are subsequently transmitted during reproduction, which can then feed back into sequence modification of DNA itself.
These epigenetic changes - chemical modifications and markers that change the way enzymes and regulatory proteins have access to DNA - are currently being studied to explain many non-Mendelian patterns of inheritance. The best understood mechanism is nucleotide methylation
DNA methylation
DNA methylation is a biochemical process that is important for normal development in higher organisms. It involves the addition of a methyl group to the 5 position of the cytosine pyrimidine ring or the number 6 nitrogen of the adenine purine ring...
that silences a gene. Methylation can be inherited during cell division, both asexually (mitotic) during development and wound healing, but in some instances also sexually (meiotic). Methylation is linked in some instances to RNA interference, the new and emerging science of RNA regulation of gene expression.
The third dimension comprises the transmission of behavioural traditions. There are for example documented cases of food preferences being passed on, by social learning, in several animal species, which remain stable from generation to generation while conditions permit. The fourth dimension is symbolic inheritance, which is unique to humans, and in which traditions are passed on “through our capacity for language, and culture, our representations of how to behave, communicated by speech and writing.”
In their treatment of the higher levels, Jablonka and Lamb distinguish their approach from the banalities of evolutionary psychology, of "memes", and even from Chomskyian ideas of universal grammar. They argue that there are constant interactions between the levels - epigenetic, behavioural and even symbolic inheritance mechanisms also produce selection pressures on DNA-based inheritance and can, in some cases, even help direct DNA changes themselves - so "evolving evolution". To liven their text, they utilise thought experiments and dialogue with a sceptical enquirer, one IM-Ifcha Mistraba, Aramaic, they say, for "the opposite conjecture".
Since publication of this book, Lamb and Jablonka have responded to critics, citing evidence which affirms their view that evolutionary change is facilitated by all types of hereditary information that they have identified: genetic, epigenetic, behavioural and cultural. They claim that their approach broadens the definitions of terms such as ‘units of heredity’, ‘units of evolution’, and ‘units of selection’, and they maintain that ‘information’ can be a useful concept if it is defined in terms of its effects on the receiver. They concede that evolutionary theory is not undergoing a paradigm shift or Kuhnian revolution, but argue that the incorporation of new data and ideas about hereditary variation, and the role of development in generating it, is leading to a very different version of Darwinism than the gene-centred one which has dominated evolutionary thinking in the second half of the twentieth century.
Publications
- Eva Jablonka and Marion J. Lamb (1995). Epigenetic Inheritance and Evolution: the Lamarckian Dimension, Oxford University Press. ISBN 0198540639, ISBN 9780198540632, ISBN 978-0198540632
- Eva Jablonka and Marion J. Lamb (2005) Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral, and Symbolic Variation in the History of Life. MIT Press. ISBN 0262101076
(First published 1990).