Erg (landform) Erg (landform) An erg (also sand sea or dune sea, or sand sheet if it lacks dunes) is a broad, flat area of desert covered with wind-swept sand with little or no vegetative cover. The term takes its name from the Arabic word "ʿarq" (), meaning "dune field". Strictly speaking, an erg is defined as a desert area that contains more than of aeolian or wind-blown sand and where sand covers more than 20% of the surface. Smaller areas are known as "dune fields". The largest hot desert in the world, the Sahara, covers and contains several ergs, such as
ERG (gene) in mature lymphocytes (types of white blood cells). Therefore, ERG may act as a regulator of differentiation of early hematopoietic cells. The Mld2 mutation, generated through an ENU mutagenesis screen, was the first non-functional allele of "Erg". Homozygous Mld2 is embryonic lethal at day 13.5. Adult mice heterozygous for the Mld2 mutation have hematopoietic stem cell defects. This means that when the ERG gene was not actively transcribed and the ERG protein produced, a mouse's hematopoietic cells were unable to function properly. Since ERG is important to the ability of the hematopoietic cells to function and self-renew, there may be