Figure 5.

Distribution patterns of gene loss in Orchidaceae. The dark blue, light blue, and white blocks indicate presence, pseudogene, and absence of each gene, respectively. The non-functionalization of 11 ndh genes are distributed widely across all taxonomic groups of Orchidaceae. This frequently occurs in Epidendroideae and Vanilloideae. The non-functionalization of psa, psb, pet, and rpo gene classes are confined to mycoheterotrophic lineages. In addition, the loss of housekeeping genes such as the rps, rpl, or trn gene classes occur independently in four genera, Epipogium, Gastrodia, Lecanorchis, and Rhizanthella. The species names in red indicate mycoheterotrophic orchids.