a, MTLa-specific genes are shown in grey, MTLα-specific genes are shown in black and other orthologues are shown in colour. Two idiomorphs from C. albicans and C. tropicalis are shown. Arrows indicate inversions relative to C. albicans. Crosses show gene losses and the C. parapsilosis MTLa1 pseudogene. There is no MTL locus in L. elongisporus; gene order around the PAPa, OBPa and PIKa genes is shown. For C. guilliermondii and C. lusitaniae, the genome project sequenced one idiomorph; the second was obtained by J. Reedy. In D. hansenii, PAP, OBP and PIK are separate from the fused MTL locus³². b, Placement of gene losses on the phylogenetic tree. HOM, homothallic; HET, heterothallic.