Genetic variation at microsatellite loci in northern populations of the European flat oyster (Ostrea edulis)

Abstract

Samples of Ostrea edulis were collected during 1999 and 2000 from five sites in Scotland, and from one site each in Northern Ireland, Ireland, France, The Netherlands and Norway. Samples were scored at four microsatellite loci. Mean numbers of alleles per locus varied from 12·6 to 16·6 and observed heterozygosity per locus ranged from 0·801 to 0·845. Samples derived originally from hatchery seed showed significantly fewer alleles per locus and significantly reduced expected heterozygosity compared with wild populations. However, observed heterozygosity did not differ significantly between the two groups. Significant deficiencies of heterozygotes were present at one or more loci in four of the ten populations sampled and a significant excess of heterozygotes was present at one locus in a hatchery-sourced Scottish population. Genetic distance indices revealed that the Norway population was the most distinct from all others and that hatchery-sourced populations were also relatively distinct from other wild populations. However, genetic subdivision was generally low implying high historical ‘migration’ rates for these populations.

The Native Oyster Restoration Alliance (NORA) and the Berlin Oyster Recommendation: bringing back a key ecosystem engineer by developing and supporting best practice in Europe

“…Preserve the extant genetic diversity of native oysters in Europe (Saavedra, 1997;Vercaemer et al, 2003;Laing, 2005;Laing et al, 2005;Sobolewska and Beaumont, 2005;University Marine Biological Station Millport, 2007;Ashton and Brown, 2009;Lallias et al, 2010) European oyster (O. edulis) and Pacific oyster (Crassostrea gigas) by translocation of Dutch broodstock oysters and by introduction of substrate (shell material) to increase reproduction and recruitment (Sas et al, 2016(Sas et al, , 2018. Monitoring of growth, health, survival, reproduction and recruitment is ongoing.…”

The invasive Manila clam Ruditapes philippinarum (Adams and Reeve, 1850) in Northern Adriatic Sea: Population genetics assessed by an integrated molecular approach

“…Reconstructing population history from a single locus could lead to an incomplete understanding of population histories (Freeland, 2005). Therefore, we combined the usefulness of 16S rRNA sequencing for phylogenetics of Venerids (Canapa et al, 2003;Kappner and Bieler, 2006;Mikkelsen et al, 2006), with the well documented potential of the highly polymorphic microsatellite loci to assess genetic diversity of bivalves (Sobolewska et al, 2001;Presa et al, 2002;Astanei et al, 2005;Sobolewska and Beaumont, 2005;Li et al, 2006;Yasuda et al, 2007;Gosling et al, 2008;An et al, 2009). …”

Identification, Inheritance, and Variation of Microsatellite Markers in the Black Scallop Mimachlamys varia

“…All deviations were associated with positive f values (0.181-0.530), indicating a heterozygote deficit, which is a very frequent occurrence in marine bivalve populations, including scallops (e.g., Benzie and Smith-Keune 2006;Hui et al 2006). Various factors such as inbreeding, the Wahlund effect, and selection could explain heterozygote deficits, but the factor more frequently considered when microsatellite loci are examined is the presence of null alleles (e.g., Sobolewska and Beaumont 2005). Although evidence of null alleles was not found in the M. varia families examined, MicroChecker analysis indicated null alleles in all cases with significant deviation from Hardy-Weinberg equilibrium (except at the locus Mva370 in Fuengirola), suggesting that the presence of such alleles is a likely cause for most of the heterozygote deficits observed here.…”