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Static and dynamic homeostasis.

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posted on 28.03.2008, 01:16 by David Basanta, Mark Miodownik, Buzz Baum

The pictures are stills of the development of 3 organisms at time steps 50, 100 and 150. Cell age is depicted using a colour key. The organisms exemplify the different types of homeostatic behaviour observed. (A) Organism #11 is static and maintains its form by ossifying, limiting the rate of cell birth, death and movement. (B) Organism #17 is dynamic and maintains an evenly balanced but high rate of cell birth and cell death. (C) In organism #18, dynamic and static regions coexist, so that cells are born at its base and die some time later in the upper regions. This generates a visible gradient of cell ages from lower (old-red) to higher (young-blue) planes. (D–F) Graphs show the impact of mutating individual genes in the genome of organisms #11(D), #17 (E) and #18 (F) on homeostasis. Genes with the highest impact on homeostasis (genes #14 and #94 in organism #17 and gene #80 in organism #18) all encode regulators of cell death (see Videos S2B and S2C).The impact of each mutation was calculated using a combination of 2-point correlation and lineal path analysis between time-steps 50, 100 and 150.