The antagonistic pleiotropy theory was proposed by Williams in 1957, whereby Williams suggest a specific type of genetic inter-trait linkage, pleiotropy, as an evolutionary explanation for senescence (Williams 2001). Pleiotropy, or inter-trait linkage exists in a way to make it difficult for the evolution process to remove an individually adverse trait, such as aging, without simultaneously removing one or more beneficial traits. To explain further, inter-trait linkage is the phenomenon where one gene controls more than one phenotypic trait in an organism, where at least one of these traits is beneficial to the organism’s fitness, with one or more trait is detrimental to fitness. In summation, the antagonistic pleiotropy hypothesis proposes
