Fig. 1

An example of the evolutionary history of a gene family and its corresponding gene tree G and species tree S. In the history diagram, species are shown as gray bands, genes within species as black lines, gene losses as empty circles. Gene identifiers start with species label; thus \(a_1\), \(a_2\) and \(a_3\) are three copies of the studied gene in species a. Duplications are highlighted by gray dotted horizontal lines, speciations by dashed lines