scholarly journals Genetic Assimilation and Canalisation in the Baldwin Effect

2005 ◽  
pp. 353-362 ◽  
Author(s):  
Rob Mills ◽  
Richard A. Watson
Keyword(s):  
Genetic Assimilation ◽  
Baldwin Effect ◽  
The Baldwin Effect

scholarly journals Transient Phenomena in Learning and Evolution: Genetic Assimilation and Genetic Redistribution

2005 ◽  
Vol 11 (1-2) ◽  
pp. 177-188 ◽  
Author(s):  
Janet Wiles ◽  
James Watson ◽  
Bradley Tonkes ◽  
Terrence Deacon
Keyword(s):  
Vitamin C ◽  
Environmental Changes ◽  
Initial Conditions ◽  
Universal Grammar ◽  
Fitness Function ◽  
Genetic Assimilation ◽  
Baldwin Effect ◽  
Transient Phenomena ◽  
The Baldwin Effect ◽  
Redistribution Effect

Deacon has recently proposed that complexes of genes can be integrated into functional groups as a result of environmental changes that mask and unmask selection pressures. For example, many animals endogenously synthesize ascorbic acid (vitamin C), but anthropoid primates have only a nonfunctional version of the crucial gene for this pathway. It is hypothesized that the loss of functionality occurred in the evolutionary past when a diet rich in vitamin C masked the effect of the gene, and its loss effectively trapped the animals in a fruit-eating lifestyle. As a result, the complex of abilities that support this lifestyle were evolutionarily bound together, forming a multilocus complex. In this study we use evolutionary computation simulations to explore the thesis that masking and unmasking can transfer dependence from one set of genes to many sets, and thereby integrate the whole complex of genes. We used a framework based on Hinton and Nowlan's 1987 simulation of the Baldwin effect. Additional gene complexes and an environmental parameter were added to their basic model, and the fitness function extended. The simulation clearly demonstrates that the genetic redistribution effect can occur in silico, showing an initial advantage of endogenously synthesized vitamin C, followed by transfer of the fitness contribution to the complex of genes that together allow the acquisition of vitamin C from the environment. As is well known in the modeling community, the Baldwin effect only occurs in simulations when the population of agents is “poised on the brink” of discovering the genetically specified solution. Similarly, the redistribution effect occurs in simulations under specific initial conditions: too little vitamin C in the environment, and its synthesis it is never fully masked; too much vitamin C, and the abilities required to acquire it are not tightly integrated. The Baldwin effect has been hypothesized as a potential mechanism for developing language-specific adaptations like innate universal grammar and other highly modular capacities. We conclude with a discussion of the relevance of genetic assimilation and genetic redistribution to the evolution of language and other cognitive adaptations.

Landscapes, Learning Costs, and Genetic Assimilation

1996 ◽  
Vol 4 (3) ◽  
pp. 213-234 ◽  
Author(s):  
Giles Mayley
Keyword(s):  
Evolutionary Process ◽  
Small Distance ◽  
Genetic Assimilation ◽  
Phenotypic Traits ◽  
Costs And Benefits ◽  
Baldwin Effect ◽  
Adaptive Processes ◽  
Adaptive Ability ◽  
The Baldwin Effect ◽  
Neighborhood Correlation

The evolution of a population can be guided by phenotypic traits acquired by members of that population during their lifetime. This phenomenon, known as the Baldwin effect, can speed the evolutionary process as traits that are initially acquired become genetically specified in later generations. This paper presents conditions under which this genetic assimilation can take place. As well as the benefits that lifetime adaptation can give a population, there may be a cost to be paid for that adaptive ability. It is the evolutionary trade-off between these costs and benefits that provides the selection pressure for acquired traits to become genetically specified. It is also noted that genotypic space, in which evolution operates, and phenotypic space, in which adaptive processes (such as learning) operate, are, in general, of a different nature. To guarantee that an acquired characteristic can become genetically specified, these spaces must have the property of neighborhood correlation, which means that a small distance between two individuals in phenotypic space implies that there is a small distance between the same two individuals in genotypic space.

scholarly journals Epigenetic inheritance and evolution: a historian's perspective

2021 ◽  
Vol 376 (1826) ◽  
Author(s):  
Laurent Loison
Keyword(s):  
Historical Context ◽  
Epigenetic Inheritance ◽  
Genetic Assimilation ◽  
Late Nineteenth Century ◽  
Historical Reconstruction ◽  
Theme Issue ◽  
Baldwin Effect ◽  
Genetic Inheritance ◽  
History Of ◽  
The Baldwin Effect

The aim of this article is to put the growing interest in epigenetics in the field of evolutionary theory into a historical context. First, I assess the view that epigenetic inheritance could be seen as vindicating a revival of (neo)Lamarckism. Drawing on Jablonka's and Lamb's considerable output, I identify several differences between modern epigenetics and what Lamarckism was in the history of science. Even if Lamarckism is not back, epigenetic inheritance might be appealing for evolutionary biologists because it could potentiate two neglected mechanisms: the Baldwin effect and genetic assimilation. Second, I go back to the first ideas about the Baldwin effect developed in the late nineteenth century to show that the efficiency of this mechanism was already linked with a form of non-genetic inheritance. The opposition to all forms of non-genetic inheritance that prevailed at the time of the rise of the Modern Synthesis helps to explain why the Baldwin effect was understood as an insignificant mechanism during the second half of the twentieth century. Based on this historical reconstruction, in §4, I examine what modern epigenetics can bring to the picture and under what conditions epigenetic inheritance might be seen as strengthening the causal relationship between adaptability and adaptation. Throughout I support the view that the Baldwin effect and genetic assimilation, even if they are quite close, should not be conflated, and that drawing a line between these concepts is helpful in order to better understand where epigenetic inheritance might endorse a new causal role.This article is part of the theme issue ‘How does epigenetics influence the course of evolution?’

The evolutionary process in talitrid amphipods and salamanders in changing environments, with a discussion of "genetic assimilation" and some other evolutionary concepts

1982 ◽  
Vol 60 (5) ◽  
pp. 733-749 ◽  
Author(s):  
Ryuichi Matsuda
Keyword(s):  
Natural Selection ◽  
Structural Changes ◽  
Evolutionary Process ◽  
Historical Review ◽  
Genetic Assimilation ◽  
Baldwin Effect ◽  
Changing Environments ◽  
Endocrine Mechanism ◽  
Environmental Induction ◽  
The Baldwin Effect

The evolutionary process of talitrid amphipods and salamanders involving neoteny in changing environments consists of the aspect of environmental induction of structural changes as a result of altered activity of the preexisting endocrine mechanism and the aspect of natural selection which results in canalization of development and genetic assimilation of the modified (neotenous) phenotype. The prevalence of genetic assimilation is discussed, along with the cases where traditional neo-Darwinism applies. By taking the fact of environment–hormonal induction of gene regulation and the aspect of natural selection into account, mechanisms of macroevolution, preadaptation, plasticity in morphogenesis, and a mode of speciation are discussed. A historical review is presented concerning the theories (the Baldwin effect and Weismann's theory) related to genetic assimilation and neo-Darwinism.

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