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Complex Adaptations and the Evolution of Evolvability
No full textComplex Adaptations and the Evolution of Evolvability
+representation problem: "evolvability critically depends on the way genetic variation maps onto phenotypic variation"
+Evidence that phenotypic variation is under genetic control: canalization; mutant phenotypes often show more variation than the wild phenotype (see p.7) "the variability of the traits itself can evolve"
+cites Halder1995: Drosophila eyeless - out-of-place eye production can be triggered by a single signal
+"genotype-phenotype map underlying theme of: genetic canalization, developmental constraints, biological versatility, developmental dissociability, morphological integration" and more
+genotype-phenotype map evolves, main selective forces: epistatic mutations, creation of new genes
+"Variability needs to be distinguished from variation" (variability: potential to vary [*dispositional* concept, not actual state but expected development of a phenotypic trait in response to genetic and environmental influences] - variation: actually realized differences between individuals)
+cites Levinton1988: generation of variability needs to be studied
+Evolution of complex adaptations requires a match between the functional relationships of the phenotypic characters and their genetic representation - cites Riedl1975: "If the epigenetic regulation of gene expression 'imitates' the functional organization of the traits then the improvement by mutation and selection is facilitated" (helps when sexual recombination, p.11)
+cites Wright1968 "Pleiotropy cannot be wholly universal" - how limit:
modularity, interaction mainly short range, less frequent between members of different complexes
+evolution of modularity: origin of differentiated animals dominated by parcellation / detachment (opposed to integration of distinct parts)
but where shall we put delimitations??
Evolving Protein Interaction Networks through Gene Duplication
No full textEvolving Protein Interaction Networks through Gene Duplicatio
Gene Duplication and the Properties of Biological Networks
No full textGene Duplication and the Properties of Biological Network
A community effect in animal development
No full textA community effect in animal development
Abstract:
In animal development, the first tissues to be formed include such major components as muscle, nerve cord, notochord and the eye. In the vertebrates, all of these tissues are formed by embryonic induction, a process by which some of the cells within a mass of tissue are caused to change their direction of differentiation as a result of close proximity to cells of another kind. The induced cells typically form a solid coherent mass with a distinct border between them and the remaining uninduced cells. This clean separation between induced and uninduced cells is much sharper than can readily be explained as a result of the induction process. We describe here the culture of amphibian cell and tissue recombinations in solid gels containing cytochalasin in which cell division and cell movement is inhibited during response to induction. This has revealed an effect in which the ability of a cell to respond to induction by differentiating as muscle is enhanced by, or even dependent on, other neighbouring cells differentiating in the same way at the same time. This seems to be a newly described process in animal development, termed the community effect. It helps to explain the formation of blocks of tissue from sheets of cells, and could be of widespread occurrence and significance in morphogenesis resulting from embryonic induction
The origins of Order: Self-Organization and Selection in Evolution
No full textThe origins of Order: Self-Organization and
Selection in Evolutio
On Evolutionary Design, Embodiment, and Artificial Regulatory Networks.
No full textOn Evolutionary Design, Embodiment, and Artificial Regulatory
Networks
A Genetic Regulatory Network-Inspired Real-Time Controller for a Group of Underwater Robots.
No full textA Genetic Regulatory Network-Inspired Real-Time Controller for a Group of Underwater Robots