ABSTRACT
The inheritance of traits from parent to child has been of interest to humans for thousands of years, and the search for features that can link a newborn infant with those of the family’s ancestors is a common experience in many Western families. In 1865, the Austrian monk Gregor Mendel identified several principles of inheritance, including the principle of Independent Assortment, which states that genes at difference loci are transmitted independently. A second principle, the Principle of Segregation, also developed by Mendel, states that sexually reproducing organisms possess genes that occur in pairs and only one member of the pair is transmitted to each offspring (Jorde et al., 2003), Mendel’s work led to the identification that some alleles behave in a dominant manner, whereas others behave in a recessive manner (see ‘Further resources’ for a more complete review of this subject). In 1909, the term ‘gene’ was coined by Johannsen to describe the basic unit of heredity (Jorde et al., 2003). These principles underlie the understanding of autosomal dominant inheritance, which is one pattern of inheritance that is dependent on the basic unit of heredity. Although current understanding is continuing to be revised of both the inheritance of genes and also the potentially complex explanations for the influence of genetic and environmental factors on health and disease, much of our understanding of these influences are built on the foundations of Mendel’s laws of inheritance (Powledge, 2001).
