Genetic variation in marine molluscs.

Fujio, Yoshihisa; Yamanaka, Ryoichi; Smith, Peter

doi:10.2331/suisan.49.1809

Cited by 45 publications

(19 citation statements)

References 3 publications

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“…For all other systems the staining schemes were derived from Shaw & Prasad (1970). Subunit structures of enzymes inferred from the patterns of banding on gels were in agreement with those previously reported in the genus Mytilus, based on breeding data (Hvilson & Theisen 1984) and comparisons with related taxa (Fujio et al 1983). Loci and alleles were labelled 1, 2, 3, etc., beginning with the less-anodally migrating bands.…”

Section: Methodssupporting

confidence: 71%

A multilocus allozyme discontinuity in the mussel Mytilus galloprovincialis: the interaction of ecological and life-history factors

Quesada¹,

Zapata²,

Álvarez³

1995

Mar. Ecol. Prog. Ser.

103

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Electrophoretically detectable genetic variability of the Mediterranean mussel Mytilus galloprovincialis Lmk. was examined at 15 allozyme loci in 21 populations ranging from Santander (northern Spain) to Livorno (northwestern Italy). A major genetic break between Almeria and Alicante (southeastern Spain), as evidenced by 11 of 13 polymorphic loci examined, delimits 2 groups of populations with a high internal homogeneity. Roughly 75% of the total genetic differentiation was attributable to the divergence between these 2 groups of populations that displayed a genetic distance between them (D = 0.03) in the range of conspecific populations. This genetic break in M. galloprovincialis contrasts with earlier reports of genetic homogeneity among conspecific populations of the genus Mytilus over vast geographical distances, and represents an uncommon result in manne organisms with larval dispersal. The Zone of genetic divergence in M. galloprovincialis corresponds to a discontinuity in the distribution of this mussel, and to tbe position of the well-defined Almeria-Oran oceanographic front, with a distributional boundary between Atlantic and Mediterranean communities. In this region, other manne species exhibit similar patterns of intraspecific divergence, suggesting the action of common biogeographic processes. It is proposed that contemporary influences on gene flow related to an ecological barrier, perhaps in combination with selective pressures associated to water mass differences, maintain the abrupt change in southeastern Spain.

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Section: Methodssupporting

confidence: 71%

A multilocus allozyme discontinuity in the mussel Mytilus galloprovincialis: the interaction of ecological and life-history factors

Quesada¹,

Zapata²,

Álvarez³

1995

Mar. Ecol. Prog. Ser.

103

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“…The surplus of homozygotes frequently seen at the Pgm locus could of course theoretically indicate that homozygotes are fltter than the corresponding heterozygotes, but alternative explanations Like mixing of different genetic units (Wahlund effect) must also be considered (unless all the immigrant larvae are selected against before maturation). Such a surplus of homozygotes seems to be a common feature among marine bivalves (Fujio et al 1983, Beaumont & Beveridge 1984, Foltz & Zouros 1984, Zouros & Foltz 1984, although no unambiguous explanation for the phenomenon has been found. Moreover, the pattern of variability for Gpi and Sod revealed frequent excesses of heterozygotes, opposite to that of Pgrn and indicative of heterosis.…”

Section: Inter-sample Variation Gene Flow and Population Structuringmentioning

confidence: 99%

Genetic differentiation of the Iceland scallop Chlamys islandica (Pectinidae) in the northern Atlantic Ocean

Fevolden¹

1989

Mar. Ecol. Prog. Ser.

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Allozymic variation at gene loci encoding for glucosephosphate isomerase, phosphoglucomutase and superoxide dismutase was investigated In populations of Chlarnys islandica from waters around Jan Mayen, Spitsbergen, Bear Island and northern Norway. The Gpi locus was particularly polymorphic with at least 12 different alleles and a mean heterozygosity of 84 % Half the individuals were heterozygous at Pgm-2 and between 30 and 40 % at Sod. The high polymorphism at Gpi runs counter to an earlier hypothesis suggesting a positive correlation between environmental variability and Gpi polymorphism of pectinids. Pgm-2 and Sod revealed significant allele frequency heterogeneity among the different areas, Gpi only when the effective number of alleles was considered. The species has a large dispersal potential during a long planktonic larval stage, but information on the surface current system in the North Atlant~c suggests that restr~cted gene flow, with possible contributions from selective constraints, account for the observed pattern in gene variability. It is suggested that the conservative approach of managing each area as if it contained discrete genetic units of the species should be adopted.

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“…Significant heterozygote deficiency was also found in this study, and corroborate by the positive Fis (0.29, P) which indicates and excess of homozygous animals within each population. There are several possible explanations (relatively high levels of inbreeding, null alleles, aneuploidy, molecular imprinting, selection, Wahlund effect) which have been discussed extensively elsewhere (Fujio et al, 1983;Zouros and Foltz, 1984;Mallet et al, 1985;Gaffney et al, 1990;Beaumont, 1991;Toro and Vergara, 1995). No one of these seems either sufficient or plausible alone for M. chilensis, and the overall deficit probably results from several small effects, all tending to reduce heterozygosity, which add to a significant overall deficit.…”

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confidence: 99%

Allozymic variation and differentiation in the chilean blue mussel, Mytilus chilensis, along its natural distribution

et al. 2006

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Genetic differentiation in the Chilean blue mussel Mytilus chilensis (Hupé 1854) was investigated based on the variation in the allozyme frequencies of Pgm, Gpi, Icd, Me, Gsr, Lap and Pep in eight samples collected along 1800 km from Arauco (VIII Region) to Punta Arenas (XII Region). Despite the large geographic separations, values of Neis unbiased genetic distance, D (0.004-0.048) and standardised genetic variation among populations, Fst (0.011-0.055) were small. The levels of gene flow (Nm = 8) found in this study prevent the effect of differentiation among populations by genetic drift. This findings indicate that its long-lived planktotrophic larvae provides this species with considerable dispersal ability throughout its range which is favoured by the ocean currents along the chilean coast. In terms of management of the M. chilensis fishery, the results provide no evidence for discrete stocks, with the possible exception of the Punta Arenas population. Considering the intensive aquaculture activities with this species the present study provide preliminary data which can be used as a baseline for further characterization and /or monitoring these mussel populations.

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Genetic variation in marine molluscs.

Cited by 45 publications

References 3 publications

A multilocus allozyme discontinuity in the mussel Mytilus galloprovincialis: the interaction of ecological and life-history factors

A multilocus allozyme discontinuity in the mussel Mytilus galloprovincialis: the interaction of ecological and life-history factors

Genetic differentiation of the Iceland scallop Chlamys islandica (Pectinidae) in the northern Atlantic Ocean

Allozymic variation and differentiation in the chilean blue mussel, Mytilus chilensis, along its natural distribution

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