Developmental programs

Our studies of the ERT cell cycles show that they are regulated by nutrition (Britton Edgar 1998). If the newly hatched larva is starved for dietary amino acids, DNA replication in most ERTs is not initiated. Under starvation conditions these tissues express low levels of cyclin E and E2F, the transcription factor which is probably responsible for cyclin E expression. If either E2F or cyclin E is induced in starved larvae, DNA replication in the ERTs is activated, and thus expression of these genes appears to limit the ERT cell cycle. When nutrient-deprived larvae are fed, expression of E2F and cyclin E mRNAs increases approximately sixfold, and DNA replication is initiated in most ERT cells. If the animal is first fed and then starved, the ERT cell cycle is activated and then inactivated quite rapidly. These experiments all indicate that the ERT cell cycle is nutrition-responsive, rather than controlled by a rigid developmental program. 

Edgar BA, Lehman DA, O Farrell PH 1994 Transcriptional regulation of string(cdc25) a link between developmental programming and the cell cycle. Development 120 3131-3143... 

Lehner CF, Lane ME 1997 Cell cycle regulators in Drosophila-, downstream and part of developmental decisions. J Cell Sci 110 523-528 Liu Z, Ambros V 1989 Heterochronic genes control the stage-specific initiation and expression of the dauer larva developmental program in Caenorhabditis elegans. Genes Dev 3 2039-2049... 

The purpose of the exercise is the evolution of a "developmental program" that can guide the growth of one cell into an interconnected graph of cells... 

At every clock tick, the developmental program of each cell (in the graph of interconnected cells) computes its next state and whether it will produce a new cell or not. Division produces a new cell with exactly the same (unchangeable) developmental program as the mother cell, but with a new location = location of the mother cell + 1. Because CGP and by extension DCGP only allow feed-forward graphs, the inputs of all cells will come from external inputs and/or the outputs of other cells, which are directly/indi-rectly connected to the external inputs. Hence, if the external inputs stay stable, then so will the outputs of all the cells in the graph. 

The unmodulated functions of the developmental program of a developmental Cartesian genetic programming (DCGP) node. 

In our example, the object of evolution is a developmental program for a cell. This DP controls the growth of the cell into a graph of cells representing a mathematical function. Why would one want to effectively evolve a function A possible application is curve fitting. 

Because these systems function to maintain homeostasis, it is reasonable to presume that environmentally induced programming of the SNS and HPA axis may be part of an adaptive mechanism to enhance offspring survival. It is also conceivable that altered developmental programming of the SNS and HPA may become misguided under certain... 

All animals exhibit innate behaviors in response to specific sensory stimuli that are likely to result from the activation of developmentally programmed neural circuits. Even the activation of single classes of olfactory neurons can trigger complex behaviors [10]. The authors observed that Drosophila exhibit robust avoidance to odors released by stressed flies. When stressed, the flies emit an odorant mixture that elicits avoidance in other flies. C02 is the active component of this mixture. Specific blockade of the activation of a particular odorant receptor... 

Wilhams LM, Rudensky AY Maintenance of the Foxp3-dependent developmental program in mature regulatory T cells requires continued expression of Foxp3. Nat Immunol 2007 8 277-284. 

Most species of angiosperms produce hermaphroditic flowers. The unisexuality in some plants most often results from developmentally programmed abortion or selective reduction in sex organ primordia. In dicots, higher levels of auxins, cytokinins, and ethylene usually correlate with female sex expression and in most of them the femaleness is mainly promoted by ethylene. ... 

We are currently involved in a three phase developmental program to extend the process to other hydrogen containing streams. The program involves screening candidate streams to identify poisonous species for the metal hydrides, developing poison resistant processes for each stream, and demonstrating the process(es) on a pilot scale to establish process economics. 

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