disposition disposition inheritance pattern The pattern in which a genetic trait or condition is passed from one generation to the next, as determined by genetic interactions between alleles of the causal gene, and interactions between these alleles and the environment. The subtypes of inheritance pattern in this hierarchy are largely distinguished based on the underlying genetic mechanism, which will manifest in a characteristic pattern of traits in affected and unaffected family members. For example, 'autosomal dominant inheritance' defines an inheritance pattern that is caused by the interaction of alleles on non-sex chromosomes wherein the trait manifests even in heterozygotes - resulting in a characteristic pattern of 'dominant' inheritance across generations of individuals in a family. http://purl.obolibrary.org/obo/HP_0000005 http://purl.obolibrary.org/obo/NCIT_C45827 An inheritance pattern results from the disposition of a genetic variant to cause a particular trait or phenotype when it is present in a particular genetic and environmental context. Here, "genetic context" refers to the allelic state of the variant, which depends on what other alleles exist at the same location/locus in the genome. Zygosities such as heterozygous and homozygous are simple, common examples of 'states' of an allele. These genetic and environmental "interactions" of alleles play out at the level of the gene products produced by the causal alleles, and are observable in the pattern with which the trait caused by an allele is inherited across generations of individuals. Thus, an inheritance pattern such as dominance is not inherent to a single allele or its phenotype, but rather a result of the relationship between two alleles of a gene and the phenotype that results in a given environment. This also means that the 'dominance' of an allele is context dependent - Allele 1 can be dominant over Allele 2 in the context of Phenotype X, but recessive to Allele 3 in the context of Phenotype Y. phenotypic inheritance pattern mode of inheritance