[Update: This is how the headline should read:
Felsenstein
The paradox of sexual reproduction is the idea that there is a huge evolutionary problem with the short-term maintenance of sexual reproduction given the alternative of asexual mutants that could gain a twofold immediate advantage. This is different from the evolutionary maintenance of recombination rates above zero, because recombination rates should still gradually sink to zero, as adaptive linkage groups get ever larger, even if no asexual mutant was challenging sexual reproduction. The genome should congeal.
Among evolutionary biologists, Joe Felsenstein’s opinion is unique in that he seems to think the paradox of sex did not exist. In 1985, he expressed his opinion that there is only one problem concerning the evolution of sex and that is the problem of recombination:
“I wish to review briefly the status of this problem, and will conclude that we probably possess the elements of a sufficient explanation for the evolution of recombination, and that to have hoped for more was unrealistic. The problem has had a fascination for biologists, all the more so if it is described as ‘the evolution of sex’ rather than ‘the evolution of recombination’.” (Felsenstein 1985, p. 209)Granted that sex sells better than recombination, I still think there are two different problems at hand. Before trying to convince you of this, here’s another quote reiterating Felsenstein's position that the paradox of sex is only a marketing trick.
“Over a decade ago, I wrote two papers (Felsenstein, 1974; Felsenstein and Yokoyama, 1976) on models for the evolution of recombination. The central concern of those papers was to demonstrate the relationship between various models that had previously been proposed for the evolution of recombination and to present some simulation and theoretical results. The problem has continued to be of interest to evolutionary biologists, although they seem particularly entranced by it when it is called “the evolution of sex” rather than, more accurately, “the evolution of recombination.” When books are written on the subject, the noun in their title is inevitable “sex” rather than “recombination.” One wonders how many fewer people would buy a book on this subject if the word "sex" were not in the title.
Recently, interest in the subject seems to be increasing. In his, monograph, Williams (1975, p. v) has declared that “I hope at least to convince [readers] that there is a kind of crisis at hand in evolutionary biology, and that my suggestions are plausible enough to warrant serious considerations.” Crises in evolutionary biology have been declared quite frequently recently, although it has been noticeable that the biologist declaring one usually just happens to have completed a piece of work that is thought to solve it. These crises seem comparable in importance to the “constitutional crises” that used to be declared daily by the press during the Watergate hearings of 1973. After a time, it became clear that a constitutional crisis was somewhat less serious than a flat tire on your car.” (Felsenstein1988, p. 74)Williams did respond to Felsenstein's claim in the last chapter of the same volume called ‘Retrospect on sex and kindered topics.’ It is a specification of what Williams meant by the cost of meiosis, another highly confusing issue that I deal with here. What irritates me is that Felsenstein does not only argue that crisis is too strong a term for what he regards as a normal scientific problem, but that he denies there is a problem with the maintenance of sex beyond the maintenance of recombination. Here’s my two-pence on why I think two different problems are involved.
Suppose a species with environmental sex determination as in crocodiles. Now assume you could somehow switch off recombination, that is, all chromosomes would fuse and the two remaining, homologous giant chromosomes would be genetically identical in all base-pairs. The latter guarantees that even crossing-over during meiosis has no recombining effect. The resulting species would nevertheless be a sexual species with males, females, meiosis, but no recombination.
While this hypothetical species does not exist anywhere, the opposite exist in bacteria, organisms with no sex but recombination.
References
- Felsenstein J (1974) The evolutionary advantage of recombination. Genetics 78: 737-756.
- Felsenstein J, Yokoyama S (1976) The evolutionary advantage of recombination II. Individual selection for recombination. Genetics 83: 845-859.
- Felsenstein J (1985) Recombination and sex: Is Maynard Smith necessary? In: Greenwood PJ, Harvey PH, Slatkin M (eds) Evolution: Essays in honour of John Maynard Smith. Cambridge University Press, pp. 209-220.
- Felsenstein J (1988) Sex and the evolution of recombination. In: Michod RE, Levin BR (eds) The evolution of sex: an examination of current ideas. Sinauer Associates, Sunderland, MA, pp. 74-85.
- Williams GC (1975) Sex and evolution. Princeton University Press.
