The Genial Gene

The theory of evolution through natural selection explains the characteristics of living creatures as consequences of competition for scarce environmental resources. Charles Darwin argued that random changes occur across generations. Some of these changes provide a competitive advantage and therefore tend to be retained and passed on to offspring. Darwin worked before the discovery of genetic material, so he did not know exactly how the changes come about or are conveyed from parents to their young, but his theory received support from modern genetics, and Darwinian evolution has become the mainstay of biology. However, Darwin believed that some characteristics could not be readily explained as adaptations to an environment. The most famous example is the colorful tail of the peacock, which does not seem to provide any competitive edge to its possessor. Darwin therefore suggested that some traits are consequences of competition for mates of the opposite sex, which results in the retention of the features that provide the greatest success in mating.

The concept of sexual selection is today widely accepted, although it is not as central as natural selection is to evolutionary biology. Sexual selection often involves conflict, most obviously when it entails members of one sex, normally males, fighting with one another for the opportunity to mate with a member of the opposite sex. However, there is also conflict in mate selection among animals of different sexes, since each seeks the mate that will enable it to pass on its own characteristics. From this perspective, males will often seek multiple partners because they can maximize their chances at reproduction by fertilizing many different females. Females, though, produce a small number of eggs and therefore maximize their reproductive chances by selecting the male with the most adaptive qualities, rather than by mating with as many as possible. In this way, mate selection not only encourages competition among males but also creates a conflict of interests between males and females. By nature, and not simply in specific human societies, males tend to be polygamous and females tend to be monogamous because they are engineered by biology to have different and opposing reproductive interests.

While sexual selection is the main target of Joan Roughgarden’s book The Genial Gene, the author also intends some criticism of another major trend in evolutionary biology that incorporates sexual selection. The British biologist and ethologist Richard Dawkins provided a “gene-centered” way of looking at all evolution, including sexual selection, in his influential 1976 book The Selfish Gene. Dawkins used the adjective “selfish” metaphorically, intending to convey a view of evolution as a matter of genes successfully making copies of themselves over time, not as a matter of the well-being or survival of entire organisms. Thus, unselfish behavior on the part of organisms, such as self-sacrifice for the sake of a near relative, could be understood as rooted in the “selfishness” of the genes possessed in common by near relatives. Some critics have argued that Dawkins used a misleading metaphor, since genes have no motivation, either selfish or unselfish.

The title of The Genial Gene plays on the title of Dawkins’s famous book. However, the primary target of biologist Joan Roughgarden is not the gene-centered view of evolution but the conflict-based approach to evolution implied by focusing on sexual selection. Roughgarden believes that mainstream sexual-selection views impose cultural gender stereotypes on scientific explanations, although she acknowledges that this does not necessarily make the sexual selection explanation false. She argues, however, that the explanation is inconsistent with reasoning and empirical evidence.

According to Roughgarden, contemporary research suggests that theories of sexual selection do not even account adequately for the most classically cited case, the peacock’s tail. The elaborate tail of the peacock, in the traditional argument, evolved because it showed to peahens that the male was so fit that it could survive even with such a huge signal to predators and disadvantage in escaping from predators. Roughgarden cites a 2008 study that found that peahens showed no preference for peacocks with more elaborate trains. Instead, she maintains, the evidence indicates that the birds’ multicolored tails serve as means of communication. In the distant past, both sexes had these ornaments....

(The entire section is 1851 words.)