Random mating is the null model central to population genetics. One assumption behind random mating is that individuals mate an infinite number of times. This is obviously unrealistic. Here we show that when each female mates a finite number of times, the effective size of the population is substantially decreased.

LTHOUGH DARWIN (1871) believed that sexual selection was quite dis-A tinct from natural selection, the modern definitions of natural selection (HALDANE 1932; HUXLEY 1938, 1942) include the mating process among the forces of natural selection. DARWIN'S emphasis on the importance of male competition and the preferences of the females in sexual selection has been shown to have been misplaced in mo...

I use multilocus genetics to describe assortative mating in a competition model. The intensity of competition between individuals is influenced by a quantitative character whose value is determined additively by alleles from many loci. With assortative mating based on this character, frequencyand density-dependent competition can subdivide a population with an initially unimodal character distr...

Evolutionary Algorithms (EAs) (Bäck, 1996) mimic the process of natural selection by recombining the most promising solutions to a problem from a population of individuals, each one representing a possible solution. There are several methods to select the individuals, but all of them follow the same general rule: good (or partially good) solutions must be chosen more often for recombination eve...

Testing for random mating of a population is important in population genetics, because deviations from randomness of mating may indicate inbreeding, population stratification, natural selection, or sampling bias. However, current methods use only observed numbers of genotypes and alleles, and do not take advantage of the fact that the advent of sequencing technology provides an opportunity to i...

We analyze the long-term evolution of a continuous trait subject to frequency-dependent disruptive selection, and controlled by a single diploid, additive locus. Our simple selection model is a mathematical approximation to many complex systems of ecological interactions resulting in disruptive selection, like, for example, scramble competition and habitat heterogeneity. A polymorphism of two s...

Ciliate mating systems are highly diversified, providing unique opportunities to study sexual differentiation and its implications for mating dynamics. Many species of ciliates have multiple (>2) sexes. More sexes may mean more choice and an opportunity for evolution of preferential mating. We asked if the multiple sexes of the ciliate Tetrahymena thermophila mate preferentially among each othe...