Ecological stress and sex evolution in soil microfungi

Grishkan, Isabella; Korol, Abraham B.; Nevo, Eviatar; Wasser, Solomon P.

doi:10.1098/rspb.2002.2194

Cited by 64 publications

(48 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, if background deleterious mutations are frequent, recombination has an extra advantage in aiding purifying selection and is even more likely to evolve than in the presence of beneficial mutations alone. Such a scenario was discussed by Hadany and Feldman (2005) and could explain why recombination is more likely to occur in new, stressed environments (Abdullah and Borts 2001;Grishkan et al 2003).…”

Section: Discussionmentioning

confidence: 99%

The Role of Advantageous Mutations in Enhancing the Evolution of a Recombination Modifier

2010

View full text Add to dashboard Cite

Although the evolution of recombination is still a major problem in evolutionary genetics, recent theoretical studies have shown that recombination can evolve by breaking down interference (''HillRobertson effects'') among multiple loci. This leads to selection on a recombination modifier in a population subject to recurrent deleterious mutation. Here, we use computer simulations to investigate the evolution of a recombination modifier under three different scenarios of recurrent mutation in a finite population: (1) mutations are deleterious only, (2) mutations are advantageous only, and (3) there is a mixture of deleterious and advantageous mutations. We also investigate how linkage disequilibrium, the strength of selection acting on a modifier, and effective population size change under the different scenarios. We observe that adding even a small number of advantageous mutations increases the fixation rate of modifiers that increase recombination, especially if the effects of deleterious mutations are weak. However, the strength of selection on a modifier is less than the summed strengths had there been deleterious mutations only and advantageous mutations only.

show abstract

Section: Discussionmentioning

confidence: 99%

The Role of Advantageous Mutations in Enhancing the Evolution of a Recombination Modifier

2010

View full text Add to dashboard Cite

show abstract

“…An observation done in several organisms is that they engage in sexual reproduction when the environmental conditions are stressful. This occurs, for example, in the yeast Saccharomyces cerevisiae, where meiotic recombination frequencies increase with nutrient stress (Abdullah and Borts 2001), and in other fungi collected from the soil (Grishkan et al 2003). We can expect that the effect of each deleterious mutation on fitness may depend on the environmental conditions.…”

Section: Discussionmentioning

confidence: 99%

Sex and Deleterious Mutations

Gordo

Campos

2008

Genetics

View full text Add to dashboard Cite

The evolutionary advantage of sexual reproduction has been considered as one of the most pressing questions in evolutionary biology. While a pluralistic view of the evolution of sex and recombination has been suggested by some, here we take a simpler view and try to quantify the conditions under which sex can evolve given a set of minimal assumptions. Since real populations are finite and also subject to recurrent deleterious mutations, this minimal model should apply generally to all populations. We show that the maximum advantage of recombination occurs for an intermediate value of the deleterious effect of mutations. Furthermore we show that the conditions under which the biggest advantage of sex is achieved are those that produce the fastest fitness decline in the corresponding asexual population and are therefore the conditions for which Muller's ratchet has the strongest effect. We also show that the selective advantage of a modifier of the recombination rate depends on its strength. The quantification of the range of selective effects that favors recombination then leads us to suggest that, if in stressful environments the effect of deleterious mutations is enhanced, a connection between sex and stress could be expected, as it is found in several species. S EXUAL reproduction involves exchange of geneticinformation between individuals of a given species. Why this should be advantageous remains a matter of debate (Barton and Charlesworth 1998;Agrawal 2006). The number of theories to explain the prevalence of sex in the natural world has been increasing over several decades and a pluralistic view of the evolution of sex has been suggested by some (West et al. 1999). From the population genetics perspective one of the major consequences of sex and recombination is that it can break down linkage disequilibrium created in natural populations by selection and/or genetic drift (Felsenstein 1974). Linkage disequilibrium has therefore been considered the key for understanding the maintenance of sexual reproduction. Here we take a simple view and try to quantify the minimal conditions under which sex can evolve. The minimal model we study here has been the target of recent studies (Keightley and Otto 2006) and here we explore it further. It is based on the hypothesis put forward by H. J. Muller that sexual populations are more efficient at eliminating deleterious mutations and that in asexual populations a ratchet mechanism can operate (Felsenstein 1974). Muller's ratchet is the accumulation of slightly deleterious mutations in an asexual population and its continuous genetic degeneration by the stochastic loss of its best-fit individuals. The relevant evolutionary forces in question when studying the ratchet are mutation, purifying selection, and random genetic drift. Muller's ratchet is a particular case of the more general HillRobertson effect, which states that selection at one locus affects the efficacy of selection at other linked loci (Hill and Robertson 1966;Felsenstein 1974;Comeron et al. 2008). Th...

show abstract

“…Cells with DNA damage have also been shown to undergo sex at higher rates in viruses (Bernstein 1987), bacteria (Wojciechowski et al 1989), and yeast (Bernstein and Johns 1989). In soil microfungi, sex is more common under stressful environmental conditions associated with drought severity and high salinity (Grishkan et al 2003). In four of five plant studies reviewed by van Kleunen et al (2001), there was relatively greater allocation to sexual than to vegetative reproduction at high density (competitive stress).…”

mentioning

confidence: 99%

The Evolution of Condition-Dependent Sex in the Face of High Costs

Hadany

Otto

2007

Genetics

View full text Add to dashboard Cite

Facultatively sexual organisms often engage in sex more often when in poor condition. We show that such condition-dependent sex carries evolutionary advantages and can explain the evolution of sexual reproduction even when sex entails high costs. Specifically, we show that alleles promoting individuals of low fitness to have sex more often than individuals of high fitness spread through a population. Such alleles are more likely to segregate out of bad genetic backgrounds and onto good genetic backgrounds, where they tend to remain. This ''abandon-ship'' mechanism provides a plausible model for the evolution and maintenance of facultative sex.

show abstract

Ecological stress and sex evolution in soil microfungi

Cited by 64 publications

References 35 publications

The Role of Advantageous Mutations in Enhancing the Evolution of a Recombination Modifier

The Role of Advantageous Mutations in Enhancing the Evolution of a Recombination Modifier

Sex and Deleterious Mutations

The Evolution of Condition-Dependent Sex in the Face of High Costs

Contact Info

Product

Resources

About