Components of fitness and the PGI polymorphism in the freshwater isopod Asellus aquaticus (L.) 2. Zygotic selection

Shihab, A F; Heath, David

doi:10.1038/hdy.1987.43

Cited by 13 publications

(9 citation statements)

References 17 publications

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“…Variation at PGI loci in particular, has often been shown to be associated with differences in individual fitness in both plants and animals (Shihab & Heath 1987; Patarnello & Battaglia 1992; Watt 1992; Lönn et al . 1996).…”

Section: Discussionmentioning

confidence: 99%

Changes in allozyme frequencies inFestuca ovinapopulations after a 9‐year nutrient/water experiment

et al. 2000

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Summary 1The grass Festuca ovina is an important constituent of the species-rich`alvar' grasslands on the Baltic island of O È land. Levels of allozyme polymorphism are high and variation is known to be correlated with habitat variation (soil moisture, pH and depth). 2 A 9-year ®eld experiment on species diversity provided replicate plots (in three sites) that had been subjected to six di erent experimental treatments (control; N P K; P K; N K; K; water). 3 Samples of F. ovina were collected and analyses of deviance were used to investigate associations between allele frequencies, at each of four polymorphic loci, and the nutrient/water treatments. We also used the models to estimate predicted values for the alleles in di erent nutrient/water treatments and in interactions involving the nutrient/water treatments and additional explanatory variables (vegetation height and clipping). 4 There were signi®cant allozyme frequency di erences between samples of F. ovina from the six di erent nutrient/water treatments in the grassland experiment. Frequencies in the fertilized or watered plots had diverged from those in the control plots. There were also signi®cant allele±habitat associations (after the removal of site e ects), especially at the Pgi-2 locus. 5 Soil moisture was the only variable that was common to this study and an earlier study of variation in F. ovina in natural habitats. In natural populations, the Pgi-2-2 allele was signi®cantly associated with soil moisture and was more common in dry habitats. Our ®ndings that the frequency of the Pgi-2-2 allele was signi®cantly a ected by the nutrient/water treatments, and that it was rarest in the treatment that involved the addition of extra water, were therefore as predicted. 6 The study supports the conclusion, from an earlier study of populations in unmanipulated grassland habitats, that selection is contributing to the ®ne-scale patterning of genetic variation in the alvar populations of F. ovina.

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Section: Discussionmentioning

confidence: 99%

Changes in allozyme frequencies inFestuca ovinapopulations after a 9‐year nutrient/water experiment

et al. 2000

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“…The relationship between fitness and enzyme activity has been discussed in numerous studies (GPI: Krause 1995, Zera 1987MPI: De La Fuente et al 1986, Hernandez & De La Fuente 1988, see also Schmidt & Rand 1999, and many have related spatial variation in allele frequencies to environmental factors such as temperature (Grant et al 1992), salinity (Theisen 1978), low oxygen concentration (Shihab & Heat 1987) and pollution (heavy metals: Lavie & Nevo 1982, Hvilsom 1983, Nevo et al 1983, Patarnello et al 1991petrochemical agents: Lavie et al 1984). In our experiments, there is no obvious relationship between temperature and the population structure at the GPI* or MPI* loci.…”

Section: Selection On Newly Settled Spatmentioning

confidence: 99%

Fecundity, growth rate and survivorship at the interface between two contiguous genetically distinct groups of Semibalanus balanoides

Brind’Amour¹,

Bourget²,

Tremblay³

2002

Mar. Ecol. Prog. Ser.

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On the western coast of the Atlantic, according to the literature, 2 distinct groups of Semibalanus balanoides occur with a distinct interface near the Miramichi Estuary, New Brunswick, in the Gulf of St. Lawrence. On each side of this interface, the groups are characterized by clinal variations for MPI (mannose-6-phosphate isomerase) and GPI (glucose-6-phosphate isomerase). The present study was carried out to determine whether selection occurs at this interface, to establish how early in the sessile life period it occurs and to examine the selecting forces involved. Reciprocal transplant experiments of newly settled individuals to both sides of the interface were carried out. No significant differences specifically linked to source or destination were observed in growth or fecundity for the 2 groups at the sites studied for either control or transplanted individuals. However, differences in survival were observed; individuals transplanted south of the estuary showed lower survival than individuals transplanted north. An allozyme analysis of barnacle survivors for MPI and GPI, 2 alleles whose frequencies are known to vary abruptly in this region, indicated a change of allele frequency in transplanted individuals. The transplants' allele frequencies came to resemble those of adults from target sites, while no change occurred in transplanted individuals at control sites. Taken together with previous results, our study suggests that selection occurs very early in the newly settled individuals (spat).

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“…The common homozygote had higher fecundity than heterozygotes for Pgi in Asellus aquaticus (Shihab and Heath, 1987 that zygotic selection may favour heterozygotes at some times of the year (Shihab and Heath, 1987b). Heterozygotes appeared to have the lowest zygotic fitness at the Est locus in the fish Z. viviparus, and extensive studies have not revealed a counteracting selection component that would result in a balanced polymorphism (Christiansen et a!., 1973(Christiansen et a!., , 1977; one possibility is that heterozygotes swim slightly faster and were better able to escape being caught in the nets.…”

Section: Juvenile Zygotic Selectionmentioning

confidence: 99%

Selection component analysis of the Mpi locus in the amphipod Platorchestia platensis

McDonald

1989

Heredity

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Genotype frequencies of gravid females and their offspring, of non-gravid females, and of adult males were measured for the Mpi locus in a natural population of the amphipod Platorchestia platensis. These gave tests of gametic, sexual, fecundity and zygotic selection. The genotype distribution of adult males was significantly different from that of adult females. There were more heterozygous males than expected, suggesting that zygotic selection and not immigration produced the difference between the sexes.

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Components of fitness and the PGI polymorphism in the freshwater isopod Asellus aquaticus (L.) 2. Zygotic selection

Cited by 13 publications

References 17 publications

Changes in allozyme frequencies inFestuca ovinapopulations after a 9‐year nutrient/water experiment

Changes in allozyme frequencies inFestuca ovinapopulations after a 9‐year nutrient/water experiment

Fecundity, growth rate and survivorship at the interface between two contiguous genetically distinct groups of Semibalanus balanoides

Selection component analysis of the Mpi locus in the amphipod Platorchestia platensis

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