Hot Spots in Chromosomal Breakage: From Description TC Etiology

Positive and Negative Feedback: Striking a Balance Between Necessary Antagonists

“…In 1980, Thomas made the conjecture that ''the presence of a positive circuit in the logical structure of an autonomous differential system is a necessary, although not sufficient, condition for multistationarity'' (Thomas, 1981). The conjecture has been proven in the case of boolean networks (see Aracena et al, 2000;Demongeot et al, 2000b), and partial demonstrations in the case of continuous systems have been given (Plathe et al, 1995, as well as Snoussi, 1998Gouz! e, 1998, introduced by Demongeot, 1998, but their usefulness is deeply undermined by restrictive hypotheses.…”

Evolution and RNA Relics. A Systems Biology View

“…On Fig. 14, we can see a correlation between the localizations of the rearrangements due to translocations or crossing-overs on the human chromosome 3, and those of the genic expression, in particular the ubiquitary one which occurs during all the cell cycle (Faraut and Demongeot 2000;Demongeot et al 2000). This correlation is not surprizing because that means that DNA sites being in transcription are more fragile than those that are compacted in the nuclear chromatin.…”

Regulatory Networks Analysis: Robustness in Morphogenesis Regulation

“…That illustrates the fact that the nature adopts the best strategy for fulfilling the vital functions of an organism, like the tissue renewal (cells proliferation) and the morphogenesis. Many other examples of regulatory networks exist particularly in embryology [8][9][10][11][12][13][14][15][16][17]41] and the dynamics of the corresponding interactions graphs is still to explore: certains recent results about the role of the positive loops [35,39], the disappearance of the limit cycles by leaving the synchronous updating modes (it is in general impossible to keep the same limit cycle for all the updating modes [29]), the role of the pauci-genetic motifs [26,30,33,38] and the influence of the noise [34], as well as the results presented in [24] show that many open questions about the regulatory networks dynamics remain to be studied more precisely in the future.…”