Dictyostelium discoideum, commonly known as slime mold, is a species of soil-living amoeba. It has the remarkable ability to switch from a solitary to a multicellular form. Under certain conditions, such as starvation, individuals aggregate and differentiate to generate a spore-releasing fruiting body. Since it is relatively easy to cultivate and manipulate in the laboratory, D. discoideum is a popular eukaryote model organism for researchers studying basic cellular processes such as chemotaxis, phagocytosis, apoptosis, signal transduction and cell differentiation.

The genome was sequenced in 2005, has a size of 34 Mb, and contains approximately 12,500 protein-coding genes. It has an unusually high repeat number and is also AT-rich (approximately 78%), making sequencing and assembly particularly challenging.