Invasion genetics of the Pacific oyster Crassostrea gigas in the British Isles inferred from microsatellite and mitochondrial markers
|Author(s)||Lallias Delphine1, Boudry Pierre2, Batista Frederico3, Beaumont Andy4, King Jonathan W.1, Turner John R.4, Lapegue Sylvie5|
|Affiliation(s)||1 : Bangor Univ, Coll Nat Sci, Sch Ocean Sci, Ctr Appl Marine Sci, Menai Bridge LL59 5AB, Anglesey, Wales.
2 : IFREMER, Lab Sci Environm Marin UMR LEMAR, Unite Rech Physiol Fonct Organismes Marins, CS 10070, F-29280 Plouzane, France.
3 : Inst Portugues Mar & Atmosfera, Div Aquicultura & Valorizacao, Estacao Expt Moluscicultura Tavira, P-8700305 Olhao, Portugal.
4 : Bangor Univ, Coll Nat Sci, Sch Ocean Sci, Menai Bridge LL59 5AB, Anglesey, Wales.
5 : IFREMER, Lab Genet & Pathol Mollusques Marins, LGPMM, SG2M, F-17390 La Tremblade, France.
|Source||Biological Invasions (1387-3547) (Springer), 2015-09 , Vol. 17 , N. 9 , P. 2581-2595|
|WOS© Times Cited||26|
|Keyword(s)||Invasion genetics, Marine mollusc, Microsatellites, mtDNA, Pacific oyster, Crassostrea gigas|
|Abstract||The Pacific oyster, Crassostrea gigas, native to northeast Asia, is one of the most important cultured shellfish species. In Europe, Pacific oysters first settled along the Atlantic coasts of France at the end of the 1960s but rapidly spread and are now widely established. Twenty-two sites in the United Kingdom (UK), Ireland, Denmark, France and Spain were sampled to assess genetic diversity and differentiation. Hatchery-propagated stocks from two hatcheries located in the UK also were included. Two main genetic clusters were identified from pairwise genetic differentiation indexes, Bayesian clustering methods or neighbour-joining analysis, based on 7 microsatellite loci: (1) a Northeast cluster (including feral samples from East England, Ireland and Denmark as well as UK hatchery stocks) and (2) a Southwest cluster (including samples from South Wales, South West England, France and Spain). The Southwest cluster had significantly higher allelic richness (A) and expected heterozygosity (He) (A: 45.68, He: 0.928) than in the Northeast (A: 26.58, He: 0.883); the two diverging by a small but significant FST value (FST=0.017, 95% CI: 0.014-0.021). A 739-bp fragment of the major noncoding region of the mitochondrial genome was sequenced in 248 oysters from 12 of the studied samples in Europe and in 25 oysters from Miyagi prefecture (Japan). A total of 81 haplotypes were found. Haplotype frequency analyses identified the same two clusters observed using microsatellites. This study highlights how the number and size of introduction events, aquaculture practices, genetic bottlenecks followed by genetic drift and natural dispersal can act concurrently to shape the genetic diversity and structure of introduced populations.|