What major type of inheritance involves only one allele from each parent influencing a single trait?

Mendelian inheritance refers to the set of principles regarding the transmission of genetic traits from parents to offspring, as established through the work of Gregor Mendel. This type of inheritance is characterized by the influence of a single allele from each parent on a specific trait, which can display clear dominant and recessive relationships. For example, if we consider a trait governed by a single gene, the phenotype of the organism will be determined by the combination of one allele from the mother and one from the father.

This simplicity in inheritance patterns is evident in traits like flower color in pea plants, where the dominant and recessive traits can be easily observed through observable phenotypes in the offspring. This clear-cut manner of inheritance stands in contrast to polygenic inheritance, where multiple genes contribute to a single trait, resulting in a continuous range of phenotypic outcomes. Non-Mendelian inheritance encompasses a variety of patterns that don't follow Mendel's laws, including incomplete dominance and codominance. Epigenetic inheritance involves changes in gene expression that do not directly alter DNA sequences, yet still affect how traits are expressed. These complexities make Mendelian inheritance distinct in its straightforward mechanism of one allele from each parent influencing a single trait.