Figure 2
From: GIGA: a simple, efficient algorithm for gene tree inference in the genomic age
GIGA rules for speciation events. Note that GIGA Rules 1 and 2 result in a different tree topology than standard agglomerative methods such as UPGMA. Because GIGA uses knowledge of the species tree, it postulates that the yeast MET13/met9 group is actually orthologous to the MTHFR genes from other organisms, but was not merged prior to the sequence from D. discoidieum (DICDI) due to accelerated evolutionary rate in the fungal lineage.