Many intriguing questions remain unresolved. Social amoebas are the only known organisms that use cAMP as extracellular signal. How did this role of cAMP originate in the first place? cAMP signals are produced by oscillating pacemakers. Are these dynamics unique for cAMP or are other chemoattractants, such as glorin, also released in an oscillatory manner? Are other D. discoideum signal molecules, such as DIF, ammonia, SDF, PSF and CMF conserved throughout the phylogeny?