At its heart, sex is a process of genetic mixing: it creates unique sets of genes and trait combinations different from either of the two parents. In eukaryotes (organisms such as animals and plants), the molecular machinery of recombination deliberately breaks the chromosomes into chunks, only to reunite the pieces of maternal and paternal origin into novel permutations that are then passed on to the progeny: a remarkable act of molecular wizardry, perfected over billions years of evolutionary tinkering.
But it is not the molecular workings of recombination that captivates biologists the most, it’s the fact that genetic mixing in the form of sex has evolved in the first place, in spite of it being a cumbersome and costly endeavour. Evolutionary theorists agree that cloning, in many ways, is a more efficient mode of reproduction, which, in a world governed by the rules of natural selection, should readily outcompete sex. An asexual female, for example, would produce twice as many offspring as the sexual one, avoiding the burden of bearing males or searching for suitable mating partners./.../