An example of a quartet spectrum. The x-axis represents the quartets, one per column, arranged in descending order of the number of gene families supporting the plurality/reference topology of each quartet. For each column, the y-axis represents the number of gene families in which that quartet supports (positive y values, one topology) or conflicts (negative y values, the other two possible topologies) with the plurality or reference topology. For the conflicts, the y value represents a sum of gene families supporting the two other topologies. The spectrum is color-coded according to different bootstrap support thresholds used.
Mao et al. BMC Bioinformatics 2012 13:123 doi:10.1186/1471-2105-13-123