Pseudoallelism is a state in which two genes with similar functions are located so close to one another on a chromosome that they are genetically linked. This means that the two genes (pseudoalleles) are nearly always inherited together. Since the two genes have related functions, they may appear to act as a single gene. In rare cases, the two linked pseudoalleles can be separated, or recombined. One hypothesis is that pseudoalleles are formed as a result of gene duplication events, and the duplicated genes can undergo gene evolution to develop new functions.