Heterozygote deficiencies in a cohort of newly settled<i>Mytilus edulis</i>spat

Fairbrother, J. E.; Beaumont, Andy R.

doi:10.1017/s002531540003318x

Cited by 24 publications

(18 citation statements)

References 16 publications

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“…Zouros & Foltz (1984) proposed a model whereby selection operates against heterozygotes at the pre‐settlement stage but favours heterozygotes at the adult stage. This model is consistent with reports of heterozygote deficits in wild mussels ( Mytilus ) collected within 2–4 weeks of settlement (Gosling & Wilkins, 1985; Fairbrother & Beaumont, 1993), and also with observations that deficits tend to diminish with increasing age. Since larvae or newly settled zebra mussels were not analysed in our study, we are unable to test the model.…”

Section: Discussionsupporting

confidence: 92%

Genetic variability in Irish populations of the invasive zebra mussel, Dreissena polymorpha: discordant estimates of population differentiation from allozymes and microsatellites

2008

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1. The recent arrival and explosive spread of the zebra mussel, Dreissena polymorpha (Pallas), in Ireland provided a rare opportunity to study the population genetics of an invasive species. 2. Eight polymorphic allozyme loci (ACO-1, ACO-2, EST-D, GPI, IDH-2, MDH, OPDH and PGM) were used to investigate genetic diversity and population structure in five Irish populations, and the results were compared with those from a previous microsatellite study on the same samples. 3. The mean number of alleles per locus (2.7 ± 0.1) was similar to the mean for the same loci in European populations, suggesting that Irish founder populations were large and ⁄ or multiple colonization events took place after foundation. A deficiency of heterozygotes was observed in all populations, but was uneven across loci. 4. Pairwise comparisons, using Fisher's exact tests and F ST values, revealed significant genetic differentiation among populations. The overall multilocus F ST estimate was 0.118 ± 0.045, which contrasted with an estimate of 0.015 ± 0.007 from five microsatellite loci on the same samples in a previous study. 5. Assuming that microsatellites can be used as a neutral baseline, the discordant results from allozymes and microsatellites suggest that selection may be acting on some allozyme loci, specifically ACO-1, ACO-2, IDH-2 and MDH, which contributed most to the significant differentiation between samples.

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Section: Discussionsupporting

confidence: 92%

Genetic variability in Irish populations of the invasive zebra mussel, Dreissena polymorpha: discordant estimates of population differentiation from allozymes and microsatellites

2008

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“…Although significant, the temporal and microgeographical structures are too weak (F S1 -0.001) to generate the heterozygote deficiencies observed via a temporal or spatial Wahlund effect. Figure 1 clearly shows that the heterozygote deficiencies observed in pooled samples are essentially unaltered within temporal (or spatial) subdivisions of the sample, in agreement with previous studies observing such deficiencies, even in samples very limited in space and time (e.g., Gosling and Wilkins 1985 ;Fairbrother and Beaumont 1993). This pattern suggests some influence of inbreeding.…”

Section: Pgm-93supporting

confidence: 88%

FINE-GRAINED SPATIAL AND TEMPORAL POPULATION GENETIC STRUCTURE IN THE MARINE BIVALVESPISULA OVALIS

et al. 1997

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“…Allozyme data with locus‐specific heterozygote deficiencies form a pattern frequently found in bivalves (e.g. Lassen & Turano, 1978; Zouros et al ., 1980; Skibinski et al ., 1983; Foltz, 1986; Fairbrother & Beaumont, 1993). Proposed causes include Wahlund effects (sampling from populations with different allele frequencies), differential selection acting on larvae and/or adults, inbreeding, genomic imprinting, somatic aneuploidy and null alleles.…”

Section: Specifics Of Molecular and Morphological Datamentioning

confidence: 99%

Spatially structured genetic variation in a broadcast spawning bivalve: quantitative vs. molecular traits

Luttikhuizen

Drent

Delden

et al. 2003

Journal of Evolutionary Biology

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Understanding the origin, maintenance and significance of phenotypic variation is one of the central issues in evolutionary biology. An ongoing discussion focuses on the relative roles of isolation and selection as being at the heart of genetically based spatial variation. We address this issue in a representative of a taxon group in which isolation is unlikely: a marine broadcast spawning invertebrate. During the free-swimming larval phase, dispersal is potentially very large. For such taxa, small-scale population genetic structuring in neutral molecular markers tends to be limited, conform expectations. Small-scale differentiation of selective traits is expected to be hindered by the putatively high gene flow. We determined the geographical distribution of molecular markers and of variation in a shell shape measure, globosity, for the bivalve Macoma balthica (L.) in the western Dutch Wadden Sea and adjacent North Sea in three subsequent years, and found that shells of this clam are more globose in the Wadden Sea. By rearing clams in a common garden in the laboratory starting from the gamete phase, we show that the ecotypes are genetically different; heritability is estimated at 23%. The proportion of total genetic variation that is between sites is much larger for the morphological additive genetic variation (Q ST ¼ 0.416) than for allozyme (F ST ¼ 0.000-0.022) and mitochondrial DNA cytochrome-c-oxidase-1 sequence variation (U ST ¼ 0.017). Divergent selection must be involved and intraspecific spatial genetic differentiation in marine broadcast spawners is apparently not constrained by low levels of isolation.

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Heterozygote deficiencies in a cohort of newly settledMytilus edulisspat

Cited by 24 publications

References 16 publications

Genetic variability in Irish populations of the invasive zebra mussel, Dreissena polymorpha: discordant estimates of population differentiation from allozymes and microsatellites

Genetic variability in Irish populations of the invasive zebra mussel, Dreissena polymorpha: discordant estimates of population differentiation from allozymes and microsatellites

FINE-GRAINED SPATIAL AND TEMPORAL POPULATION GENETIC STRUCTURE IN THE MARINE BIVALVESPISULA OVALIS

Spatially structured genetic variation in a broadcast spawning bivalve: quantitative vs. molecular traits

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