A non-standard trait (e.g. natural competence) is assessed qualitatively (e.g. presence/absence) and used as a natural reporter. The observed phenotype should be described in the experimental notes.

DNA-arrays (or DNA-chips or microarrays) are flat slabs of glass, silicon or plastic onto which thousands of multiple short single-stranded (ss) DNA sequences (corresponding to small regions of a genome) have been attached. After performing a mRNA extraction in induced and non-induced cells, the mRNA is again reverse transcribed, but here the reaction is tweaked, so that the emerging cDNA contains nucleotides marked with different fluorophores for controls and experiment. Targets will hybridize by base-pairing with those probes that resemble them the most. The array can then be stimulated by a laser and scanned for fluorescence at two different wavelengths (control and induced). The ratio or log-ratio between the two fluorescence intensities corresponds to the induction level.

Quantitative PCR (or quantitative real time polymerase chain reaction) is a modification of the conventional PCR reaction used to amplify and simultaneously quantify a targeted DNA molecule. In its more standard incarnation, a inactive fluorescent dye is added to the PCR mix. This dye is activated upon binding double-stranded DNA; as the PCR iterates, there is more and more dsDNA and therefore more fluorescence intensity.