Nonallelic genes refer to any two or more genes that are not located on the same chromosome but have an effect on the same trait or feature. Other terms that can be used interchangeably with nonallelic gene include non-linked genes, unlinked genes, and independent genes. These genes are inherited independently from one another, meaning that the traits they control will not always be inherited together. This is because nonallelic genes will independently segregate during the formation of gametes, allowing for variations in traits within a population. Understanding nonallelic genes and their effects on traits is crucial in genetics and can aid in the mapping of these genes and the identification of genetic diseases.