What is a trait controlled by two alleles, one of which is dominant and the other recessive, known as?

A trait controlled by two alleles, one of which is dominant and the other recessive, is referred to as a simple genetic trait. This means that the expression of the trait is determined by a single gene locus where one allele can mask the effect of the other. In this scenario, the dominant allele will be expressed in the phenotype even if only one copy is present, while the recessive allele will only be expressed if two copies are present.

Simple genetic traits are typically easier to predict using basic Mendelian genetics, where the inheritance patterns can often be charted through Punnett squares. Examples of simple genetic traits include flower color in pea plants or certain coat colors in animals, where the traits can be traced back to clear dominant and recessive alleles.

In contrast, choices such as polygenic traits involve multiple genes contributing to a phenotype, leading to a wide variation of traits that cannot be easily predicted. A multiple allele system includes a gene with more than two forms (alleles) affecting the trait, while complex traits are influenced by multiple genes and environmental factors, making them much more intricate in terms of inheritance and expression.