Fig. 4

Epigenetic landscapes and chromatin dynamics of the Drosophila chromosome 2 L. “Virtual 3C”, obtained from Hi-C experiments in the Drosophila, were classified according to the four previously defined epigenetic domains (D1 to D4) [6]: D1 (“red chromatin”) corresponds to domains with “active” epigenetic marks, D2 (“black chromatin”) displays no specific epigenetic modifications, D3 (“blue chromatin”) is PcG associated chromatin and D4 (“green chromatin”) is HP1/heterochromatin. The unconstrained chromatin model [eqs.1 and 2] was then fitted and the three best-fit parameters (K = crosslinking efficiency; L = compaction; S = flexibility) were recovered from each “virtual 3C”. Statistical analyses of best-fit parameters were performed separately according to the epigenetic domains. Box-plots show the results obtained for each type of domains on the chromosome 2 L. Stars indicate statistically significant differences: single asterisk indicates a p-value < 0.05 and > 0.01, a double asterisk a p-value < 0.01 and > 0.001 and a triple asterisk a p-value < 0.001 (all p-values are given in Additional file 5). The number of best-fits (n) performed in each domain is as follows: D1: n = 990; D2: n = 2481; D3: n = 624; D4: n = 239). The results obtained from the other Drosophila chromosomes are given in Additional file 3