# ''Pleiotropy'', the fact that a change of a single gene can have several different effects, renders the "improvement" of animals by random mutation impossible, as any mutation with a potentially beneficial effect will be coupled with one or more other potentially lethal effects.<ref>http://www.answersingenesis.org/articles/aid/v4/n1/beneficial-mutations-in-bacteria</ref> | # ''Pleiotropy'', the fact that a change of a single gene can have several different effects, renders the "improvement" of animals by random mutation impossible, as any mutation with a potentially beneficial effect will be coupled with one or more other potentially lethal effects.<ref>http://www.answersingenesis.org/articles/aid/v4/n1/beneficial-mutations-in-bacteria</ref> |