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Figure 3. Schematic model of the evolution of the EGF-TM7 family. Steps 1 to 3 indicate gene duplications. Step 4 refers to gene conversion events that occurred among EMR2, CD97, and EMR3. At the bottom, organization of EGF-TM7 clusters in humans is shown. Additional duplications and deletions have changed the number of EGF-TM7 receptor genes in other species. Genes are shown as arrows, indicating the transcriptional orientation. Genes are depicted in dark colors when encoding two EGF domains and light colors when encoding 
five EGF domains. Maps are not to scale.
