1,721,260 research outputs found
Directed evolution of an artificial cell lineage
No full textBiological development is a complex process that mediates between genotypes, to which mutations occur, and phenotypes, on which selection acts. Properties of development can therefore have considerable impact on evolution. However, in many existing simulation models of development, the developmental process itself is difficult to recover and/or analyse. We have previously introduced a model of development in which the developmental process is represented as a cell lineage. Here we use this model to further explore the control of development, and the influence that development has on shaping an adaptive landscape
Wiles, J A, SX6553
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/425713Surname: WILES. Given Name(s) or Initials: J A. Military Service Number or Last Known Location: SX6553. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 22970.251930
Item: [2016.0049.57974] "Wiles, J A, SX6553
Wiles, J E, VX16067
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/425714Surname: WILES. Given Name(s) or Initials: J E. Military Service Number or Last Known Location: VX16067. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 8878.251932
Item: [2016.0049.57975] "Wiles, J E, VX16067
Stability and task complexity: a neural network model of genetic assimilation
No full textSince Hinton and Nowlan introduced the Baldwin effect to the evolutionary computation community, agent-based studies of genetic assimilation have uncovered many details of the dynamic processes involved. In a previous paper, we demonstrated genetic assimilation with a simple food/toxin discrimination task using neural network agents that could evolve their learning rate. The study reported in this paper investigated the genetic assimilation of more complex learning tasks. Kauffman's NK landscape model, which can generate landscapes with a variable degree of correlation, was used to define learning tasks of varying levels of complexity. Simulations indicate an increased tendency of genetic assimilation to occur as the complexity of the learning task decreases and the environmental stability increases. These results are explained in terms of the shifting balance between the evolutionary costs and benefits of learning
LinMap: visualising complexity gradients in evolutionary landscapes
No full textThis paper describes an interactive visualisation tool, LinMap, for exploring the structure of complexity gradients in evolutionary landscapes. LinMap is a computationally efficient and intuitive tool for visualising and exploring multidimensional parameter spaces. An artificial cell lineage model is presented that allows complexity to be quantified according to several different developmental and phenotypic metrics. LinMap is applied to the evolutionary landscapes generated by this model to demonstrate that different definitions of complexity produce different gradients across the same landscape; that landscapes are characterised by a phase transition between proliferating and quiescent cell lineages where both complexity and diversity are maximised; and that landscapes defined by adaptive fitness and complexity can display different topographical features
The integration of cognitive knowledge into a perceptual representation: Lessons from Human and Computer Go
No full textA gene regulatory network for cell differentiation in Caenorhabditis elegans
No full textBiological development is a remarkably complex process. A single cell, in an appropriate environment, contains enough information to produce a wide variety of specialised cell types, whose spatial and temporal dynamics interact to form intricately detailed patterns and behaviour. Much of the complexity of a developing system lies in the dynamics of gene regulation that occur within each cell. We used a simple recurrent network to model the process of gene regulation and evolved systems that were able to generate the first four cell divisions of the C. elegans cell lineage tree with a high degree of accuracy
Investigating ontogenetic space with developmental cell lineages
No full textDevelopment plays a significant role in biological evolution, and is likely to prove an effective route to overcoming the limitations of direct genotype-phenotype mappings in artificial evolution. Nonetheless, the relationship between development and evolution is complex and still poorly understood. One question of current interest concerns the possible role that developmental processes may play in orienting evolution. A first step towards exploring this issue from a theoretical perspective is understanding the structure of ontogenetic space: the space of possible genotype-phenotype mappings. Using a quantitative model of development that enables ontogenetic space to be characterised in terms of complexity, we show that ontogenetic landscapes have a characteristic structure that varies with genotypic properties
A comparison of neutral landscapes - NK, NKp and NKq
No full textRecent research in molecular evolution has raised awareness of the importance of selective neutrality. Several different models of neutrality have been proposed based on Kauffman’s well-known NK landscape model. Two of these models, NKp and NKq, are investigated and found to display significantly different structural properties. The fitness distributions of these neutral landscapes reveal that their levels of correlation with non-neutral landscapes are significantly different, as are the distributions of neutral mutations. In this paper we describe a series of simulations of a hill climbing search algorithm on NK, NKp and NKq landscapes with varying levels of epistatic interaction. These simulations demonstrate differences in the way that epistatic interaction affects the 'searchability' of neutral landscapes. We conclude that the method used to implement neutrality has an impact on both the structure of the resulting landscapes and on the performance of evolutionary search algorithms on these landscapes. These model-dependent effects must be taken into consideration when modelling biological phenomena
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