There are three types of genetic disorders: 1  Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example. 2  Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. 3  Complex disorders, where there are mutations in two or more genes.
OSI model. The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to their underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols.
The OSI model is a seven-layer model developed around five specific design principles: Whenever a discrete level of abstraction is required, a new layer should be created. Each layer of the model should carry out a well-defined function. The function of each layer should define internationally standardized protocols. The boundaries of the layers should be placed to minimize the flow of information across interfaces.