Inheritance patterns are the predictable patterns seen in the transmission of genes from one generation to the next, and their expression in the organism that possesses them. (A gene is said to be expressed when it is read by cellular mechanisms that result in the production of a protein.) While people have long noted that offspring resemble parents, the formal description of inheritance patterns began with Gregor Mendel, whose discoveries laid the foundation for the modern understanding of genetic inheritance.

Phenotype and Genotype

An organism's observable characteristics, such as height, hair texture, skin color, or ear shape, are known as the phenotype of that organism. The phenotype is determined partly by the environment and partly by the set of genes that the organism inherited from its parents. Adult height, for instance, is due partly to nutrition (an environmental influence), and partly to a set of genes...