Effects of isolation by distance and geographical discontinuity on genetic subdivision of Littoraria cingulata

Johnson, M. S.; Re, Black

doi:10.1007/s002270050395

Cited by 37 publications

(27 citation statements)

References 19 publications

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“…In western Australia, the gastropod Littorina cingulata shows marked isolation by distance over spatial scales of up to 300 km, but not on scales from 400 to 1000 km (Johnson and Black 1998). Genetic distance (G ST ) was estimated from 22 allozyme loci, and increased at the rate of 0.07/1000 km among populations sampled closely together.…”

Section: Discussionmentioning

confidence: 99%

“…Comparisons between geographically disjunct populations frequently generate much of the signal in isolation-bydistance comparisons (e.g., crown-of-thorns starfish, Benzie and Stoddart 1992). Ideally, short-range larval dispersal should be measured through genetic isolation by distance of relatively close populations (see Hellberg 1994, Johnson andBlack 1998), and be compared with estimates based on genetic analyses across larger distances. In addition, it would be valuable to examine simulations in which dispersal discontinuities were built into the geographic arrangement of demes.…”

Section: Discussionmentioning

confidence: 99%

“…Interestingly, Slatkin (1993) has demonstrated that isolation by distance in a stepping-stone model can be visible in closely spaced populations, but invisible in widely spaced populations if the set of demes is far from equilibrium. Whether the instances of marine population uniformity are due in part to studies of nonequilibrium populations at too high a spatial scale (see Hellberg 1994, Johnson andBlack 1998) or due to truly high larval dispersal is an important issue to resolve.…”

Section: Discussionmentioning

confidence: 99%

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Population Genetics, Demographic Connectivity, and the Design of Marine Reserves

Palumbi

2003

Ecological Applications

1,009

974

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Abstract. Genetic analyses of marine population structure often find only slight geographic differentiation in species with high dispersal potential. Interpreting the significance of this slight genetic signal has been difficult because even mild genetic structure implies very limited demographic exchange between populations, but slight differentiation could also be due to sampling error. Examination of genetic isolation by distance, in which close populations are more similar than distant ones, has the potential to increase confidence in the significance of slight genetic differentiation. Simulations of one-dimensional stepping stone populations with particular larval dispersal regimes shows that isolation by distance is most obvious when comparing populations separated by 2-5 times the mean larval dispersal distance. Available data on fish and invertebrates can be calibrated with this simulation approach and suggest mean dispersal distances of 25-150 km.Design of marine reserve systems requires an understanding of larval transport in and out of reserves, whether reserves will be self-seeding, whether they will accumulate recruits from surrounding exploited areas, and whether reserve networks can exchange recruits. Direct measurements of mean larval dispersal are needed to understand connectivity in a reserve system, but such measurements are extremely difficult. Genetic patterns of isolation by distance have the potential to add to direct measurement of larval dispersal distance and can help set the appropriate geographic scales on which marine reserve systems will function well.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Population Genetics, Demographic Connectivity, and the Design of Marine Reserves

Palumbi

2003

Ecological Applications

1,009

974

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“…Isolation by distance has been shown in species with large distributions relative to their dispersal capability (e.g. Hellberg 1994, Palumbi et al 1997, Johnson & Black 1998 of populations within a widely distributed population. Pair-wise comparisons of genetic distances, measured as F st , of populations on the regional scale of the fjords on the west coast of the South Island showed no correlation, and large residuals indicate that genetic drift is more influential than gene flow (Hutchinson & Templeton 1999).…”

Section: Discussionmentioning

confidence: 99%

Genetic subdivision of a sea star with high dispersal capability in relation to physical barriers in a fjordic seascape

Sköld¹,

Wing²,

Mladenov³

2003

Mar. Ecol. Prog. Ser.

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We used allozymes to investigate the population genetics of the sea star Coscinasterias muricata throughout New Zealand, with emphasis on populations inhabiting the fjords on the west coast of the South Island. Mean genetic variability measured by Wright's F st for all the New Zealand populations was 0.061, indicating a moderate level of genetic divergence on a New Zealand wide scale. F st for populations from the fjord region was generally lower, ranging from 0.024 to 0.028, but it deviated from zero for all the loci examined. Evidence of isolation by distance was found when all populations were used in an analysis of log of the extent of gene flow between a pair of populations (M ) against the log of geographic distance (r 2 = 0.57, p < 0.001, Mantel test). Thus, a pattern of isolation by distance seems evident on this larger scale. However, pair-wise comparisons of genetic distances, measured as F st , of populations on the regional scale of the fjords on the west coast of the South Island showed no correlation, since high variation of F st (0.001 to 0.09) between populations separated by 20 to 105 km was detected. The overall pattern of genetic variation revealed in a cluster analysis of genetic identity, I, grouped all the fjord populations together with maximum genetic identities of 94.6% to the other South Island populations, but within the fjord region, populations were not segregated according to geographical location. We suggest that the relatively isolated hydrography of each fjord is a most likely explanation for why fjord populations form genetic clusters that are inconsistent with geographical distance. The New Zealand fjords changed from freshwater systems about 12 000 to 6500 yr ago, and genetic equilibrium for the populations that colonized the fjords may not have been reached yet. We suggest that the recent colonization of the fjords, and the physical isolation from the open coast and each other, are important in explaining the genetic pattern of fjord populations of C. muricata.

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“…The area between Fanore and Inveran is not continuous adult habitat (areas of soft sediment are present) and although this may explain some of the genetic differentiation (Johnson & Black 1998), it is unlikely to explain it all; there was twice as much gene flow between Inishmaen and these 2 mainland sites as there was between Fanore and Inveran, even though all the sites are approximately equidistant. Further explanations may include a salinity cline between these sites from freshwater input or local hydrographic conditions (possibly due to freshwater flow from Galway Bay) inhibiting rafting or the movement of dislodged egg capsules between these sites (Swearer et al 1999, Hellberg et al 2002.…”

Section: Local Barriers To Gene Flowmentioning

confidence: 99%

Similarity in connectivity patterns for two gastropod species lacking pelagic larvae

Bell¹

2008

Mar. Ecol. Prog. Ser.

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Marine species have a wide range of reproductive strategies that are considered to influence genetic structuring and connectivity between populations. Generally, species without planktonic larvae have reduced dispersal and gene flow between populations compared to species with free-living pelagic larvae. Further divisions exist within non-planktonic species including those exhibiting viviparity and oviparity. Although dispersal potential and population connectivity patterns of these 2 reproductive modes are considered similar, there is little supporting evidence. I examined genetic structuring and gene flow between oviparous and viviparous gastropod populations separated at the same spatial scales (at the same sites). Population genetic structure (using microsatellite data) was compared between island -mainland, mainland -mainland and island -island populations for an egg-laying (Nucella lapillus: oviparous) and a brooding (Littorina saxatilis: ovoviviparous) gastropod species. N. lapillus generally had lower levels of genetic differentiation between populations (R ST ranged between 0.01 and 0.20; F ST ranged between 0.01 and 0.17) than L. saxatilis (R ST ranged between 0.02 and 0.21; F ST ranged between 0.02 and 0.19); these differences were small for all site comparisons. Significant correlations were found between genetic structuring and gene flow patterns for the 2 species, indicating similar dispersal routes and population connectivity patterns. This study shows that it may be possible to generalise connectivity patterns (i.e. dispersal routes) across species lacking pelagic larvae, which may be important for Marine Protected Area network planning.

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Effects of isolation by distance and geographical discontinuity on genetic subdivision of Littoraria cingulata

Cited by 37 publications

References 19 publications

Population Genetics, Demographic Connectivity, and the Design of Marine Reserves

Population Genetics, Demographic Connectivity, and the Design of Marine Reserves

Genetic subdivision of a sea star with high dispersal capability in relation to physical barriers in a fjordic seascape

Similarity in connectivity patterns for two gastropod species lacking pelagic larvae

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