Summary: Current Biology 16, R696R704, September 5, 2006 ª2006 Elsevier Ltd All rights reserved DOI 10.1016/j.cub.2006.07.063
ReviewEvolution of Sex: Why Do
Organisms Shuffle Their Genotypes?
Aneil F. Agrawal
Sexual processes alter associations among alleles.
To understand the evolution of sex, we need to
know both the short-term and long-term conse-
quences of changing these genetic associations.
Ultimately, we need to identify which evolutionary
forces -- for example, selection, genetic drift, migra-
tion -- are responsible for building the associations
affected by sex.
There are a number of reasons why sex might be dis-
advantageous. In species where males provide little
or no resources to their offspring, females pay the
full cost of reproduction yet only provide half of each
sexually produced offspring's genes. In contrast, if
a female were to produce an offspring asexually, she
would transmit twice as many genes at the same ener-