Gene expression comparison between different conditions and strains was performed considering only reads uniquely mapped.
For each comparison between environmental conditions and strains we have classified the genes differentially expressed in four categories considering the degree of the differential expression (higher than two times or comprised between 1.6 and 2 times) and the p-value (lower or equal than 0.0001 and comprised between 0.0001 and 0.001) (Additional file 9: Table S11).
In addition to this comparison between the RMe and RMg samples discussed above, we computed all between-strain-within-condition, and between-condition-within-strain Pearson correlations for the BYg, RMg, RMe, and RMg samples [see Additional file 1, Table S4].
Their sensing capabilities were investigated under tensile conditions and various strain histories (strain ramp; cyclic loading-unloading tests; application of constant strain over prolonged time) aiming at highlighting the correlation between electrical response, applied strain, time and mechanical histories.
Depending on the evolutionary pressures in the environment, either high growth (in conditions of competition between species and strains) or longer survival (in scarce conditions) could contribute to fitness.
A t-test was performed on log2-transformed data to identify the genes with significant changes in expression between the two growth conditions and between the two strains.
Genes exhibiting a >2 fold log change in RPKM between two conditions or strains were considered to have differential expression.
The most common reason for presentation was injury and related conditions, split almost equally between fractures and dislocations and strains and sprains (Table 3).
As all tests were performed, under standardized laboratory conditions and the variation between strains could be attributed to the genotype, showing that most phenotypic variation has a genetic basis.
Although from the numerical results the relation between stress and strain has a small difference from the theoretical situation, the relation between the strain rate and the differential stress with the free boundary condition matches the theoretical situation very well.
