Apoptosis can be the specific mode of death that occurs during development and as such can also be referred to as programmed cell death. However, there are other forms of programmed cell death during development that are distinct from apoptosis. Identified in 1972 by Kerr et al . Apoptotic cell death is characterized by distinct morphologic changes as cells die by this mechanism. These changes include alterations of the plasma membrane due to the severing of junctions with neighboring cells, and the loss of microvilli.
Blebs also appear on the cell surface.
Chromatin condenses, forming aggregates along the nuclear membrane followed by a segmentation of the nucleus, which along with a convolution of the plasma membrane results in the formation of apoptotic bodies, which can contain intact organelles and normal mitochondria. These bodies are recognized by macrophages and adjacent cells and are rapidly phagocytosed. These oligonucleosome-sized DNA fragments, referred to as a DNA ladder, are not always associated with apoptosis. This was pointed out by Collins et. In addition, there is a step preliminary to the production of DNA laddering where DNA is digested into multiples of 300 and 50 kilobases that likely represent higher order chromatin structure.