It has long been hypothesized that gene duplications are drivers of both genome and gene function evolution. As described by Ohno (2013), when a gene duplication event first occurs, the two copies of the gene are assumed to be functionally redundant. It is believed that in most instances one copy of the gene will eventually be lost (pseudogenization or nonfunctionalization). However, as natural selection does not “know” which copy of the duplicated gene should be under selection and which should be free of selective constraint, both paralogs experience a period of relaxed selection. During this stage, it is possible that some divergence may be allowed and occasionally one copy may acquire a new function and subsequently be maintained by natural selection.