Enzyme Kinetics, Substitutable Resources and Competition: From Biochemistry to Frequency-Dependent Selection in lac

Genetics ◽  
2002 ◽  
Vol 162 (1) ◽  
pp. 485-499 ◽  
Author(s):  
Mark Lunzer ◽  
Arvind Natarajan ◽  
Daniel E Dykhuizen ◽  
Antony M Dean

Abstract Trade-offs in catalytic efficiency at the lac permease of Escherichia coli produce alleles with different substrate specializations that are selectively favored on different galactosides. We show that differential resource utilization during competition for mixtures of galactosides produces frequency-dependent selection at lac. However, the polymorphism is protected only in a narrow range of galactoside ratios despite intense selection on the pure galactosides. Hence, stabilizing frequency-dependent selection protecting natural allozyme polymorphisms through differential resource utilization will be sporadic and ephemeral in randomly changing environments. A comparison of predictions, based on first principles, with experimental outcomes reveals an additional, unanticipated source of weak selection.

2018 ◽  
Vol 115 (17) ◽  
pp. 4441-4446 ◽  
Author(s):  
Mark R. Christie ◽  
Gordon G. McNickle ◽  
Rod A. French ◽  
Michael S. Blouin

The maintenance of diverse life history strategies within and among species remains a fundamental question in ecology and evolutionary biology. By using a near-complete 16-year pedigree of 12,579 winter-run steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, we examined the continued maintenance of two life history traits: the number of lifetime spawning events (semelparous vs. iteroparous) and age at first spawning (2–5 years). We found that repeat-spawning fish had more than 2.5 times the lifetime reproductive success of single-spawning fish. However, first-time repeat-spawning fish had significantly lower reproductive success than single-spawning fish of the same age, suggesting that repeat-spawning fish forego early reproduction to devote additional energy to continued survival. For single-spawning fish, we also found evidence for a fitness trade-off for age at spawning: older, larger males had higher reproductive success than younger, smaller males. For females, in contrast, we found that 3-year-old fish had the highest mean lifetime reproductive success despite the observation that 4- and 5-year-old fish were both longer and heavier. This phenomenon was explained by negative frequency-dependent selection: as 4- and 5-year-old fish decreased in frequency on the spawning grounds, their lifetime reproductive success became greater than that of the 3-year-old fish. Using a combination of mathematical and individual-based models parameterized with our empirical estimates, we demonstrate that both fitness trade-offs and negative frequency-dependent selection observed in the empirical data can theoretically maintain the diverse life history strategies found in this population.


Genetics ◽  
1989 ◽  
Vol 122 (4) ◽  
pp. 967-976 ◽  
Author(s):  
J Mallet ◽  
N Barton

Abstract Frequency-dependent selection against rare forms can maintain clines. For weak selection, s, in simple linear models of frequency-dependence, single locus clines are stabilized with a maximum slope of between square root of s/square root of 8 sigma and square root of s/square root of 12 delta, where sigma is the dispersal distance. These clines are similar to those maintained by heterozygote disadvantage. Using computer simulations, the weak-selection analytical results are extended to higher selection pressures with up to three unlinked genes. Graphs are used to display the effect of selection, migration, dominance, and number of loci on cline widths, speeds of cline movements, two-way gametic correlations ("linkage disequilibria"), and heterozygote deficits. The effects of changing the order of reproduction, migration, and selection, are also briefly explored. Epistasis can also maintain tension zones. We show that epistatic selection is similar in its effects to frequency-dependent selection, except that the disequilibria produced in the zone will be higher for a given level of selection. If selection consists of a mixture of frequency-dependence and epistasis, as is likely in nature, the error made in estimating selection is usually less than twofold. From the graphs, selection and migration can be estimated using knowledge of the dominance and number of genes, of gene frequencies and of gametic correlations from a hybrid zone.


Evolution ◽  
1973 ◽  
Vol 27 (4) ◽  
pp. 558 ◽  
Author(s):  
R. Nassar ◽  
H. J. Muhs ◽  
R. D. Cook

2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuma Takahashi ◽  
Satoru Morita ◽  
Jin Yoshimura ◽  
Mamoru Watanabe

2010 ◽  
Vol 67 (12) ◽  
pp. 1933-1941 ◽  
Author(s):  
Barry A. Berejikian ◽  
Donald M. Van Doornik ◽  
Rob C. Endicott ◽  
Timothy L. Hoffnagle ◽  
Eugene P. Tezak ◽  
...  

As with other species, frequency-dependent selection during reproduction has long been proposed as an important mechanism in maintaining alternative male reproductive phenotypes in Pacific salmon ( Oncorhynchus spp.). Jack salmon mature one year earlier than the youngest females in a population and are much smaller than older “adult” males. We tested the hypothesis that mating success of both phenotypes is consistent with the frequency-dependent selection model. By holding male density constant and varying the frequency of adults and jacks in eight separate breeding groups, we found that adult male access to females, participation in spawning events, and adult-to-fry reproductive success increased with their decreasing frequency in a breeding group. Jacks exhibited the same pattern (increasing success with decreasing frequency), although the relationships were not as strong as for adults. Overall, jack and adult males mated with a similar number of females, but jacks sired only 20% of all offspring. Observational data suggested that adult males benefited from sperm precedence associated with their ability to court females and enter the nest first at the time of spawning. Our work provides the first experimental evidence of frequency-dependent selection during mating in the family Salmonidae.


2016 ◽  
Vol 12 (8) ◽  
pp. 20160467 ◽  
Author(s):  
Daniel I. Bolnick ◽  
Kimberly Hendrix ◽  
Lyndon Alexander Jordan ◽  
Thor Veen ◽  
Chad D. Brock

Variation in male nuptial colour signals might be maintained by negative frequency-dependent selection. This can occur if males are more aggressive towards rivals with locally common colour phenotypes. To test this hypothesis, we introduced red or melanic three-dimensional printed-model males into the territories of nesting male stickleback from two optically distinct lakes with different coloured residents. Red-throated models were attacked more in the population with red males, while melanic models were attacked more in the melanic male lake. Aggression against red versus melanic models also varied across a depth gradient within each lake, implying that the local light environment also modulated the strength of negative frequency dependence acting on male nuptial colour.


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