Ohno’s Dilemma and Cairn’s Phenomenon

ONE QUESTION in evolutionary biology not too many years ago was where new genes came from. One researcher who was influential in this area was Ohno, who described a variety of ways in which this could occur. One of the major ones is gene duplication followed by mutation, selection, and the eventual emergence of a new function for one of the gene copies. Certainly gene duplication unequivocally occurs fairly frequently–gene products that are required in large amounts frequently have multiple gene copies, and variations in gene copy numbers in humans leads to subpopulations with different phenotypes, such as faster metabolism of certain drugs.