Population structure and mantle display polymorphisms in the wavy-rayed lampmussel, Lampsilis fasciola (Bivalvia: Unionidae)

2007 ◽  
Vol 85 (11) ◽  
pp. 1169-1181 ◽  
Author(s):  
David T. Zanatta ◽  
Stephen J. Fraley ◽  
Robert W. Murphy
Keyword(s):  
North Carolina ◽  
Population Structure ◽  
Gene Flow ◽  
Tennessee River ◽  
Assignment Tests ◽  
Genotype Assignment ◽  
Little Tennessee River ◽  
Dna Microsatellite ◽  
River Drainages ◽  
Very High

Genotypes from 10 polymorphic DNA microsatellite loci were used to make assessments of population structure, measurements of gene flow, and attempts to genetically segregate polymorphic host fish-attracting mantle displays for the wavy-rayed lampmussel, Lampsilis fasciola Rafinesque, 1820 — an endangered species in Canada. Specimens were collected from seven localities — six in the Great Lakes drainages of Ontario, Canada, and one from the Little Tennessee River in North Carolina, USA. Four distinct and sympatric mantle display morphologies were observed on female L. fasciola. Displays could not be distinguished genetically using analysis of molecular variance and genotypic assignment tests. The diversity of mantle displays was correlated with the overall genetic diversity observed among populations of L. fasciola. In managing populations of L. fasciola for propagation, augmentation, and translocation, polymorphic lures should be represented in proportion to what is observed in wild populations. Through moderately high FST values and high assignment to population in genotype assignment tests, genetic structure was evident among the river drainages. Within-drainage gene flow was very high, and sampling localities within the Ontario drainages displayed panmixia. Efforts in artificial propagation and possible translocations to reintroduce or augment populations should be made to maintain the substantial levels of genetic variation while maintaining distinctiveness.

scholarly journals Distribution and population structure in the naked goby Gobiosoma bosc (Perciformes: Gobiidae) along a salinity gradient in two western Atlantic estuaries

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5380 ◽  
Author(s):  
Christopher S. Moore ◽  
Matthew J. Ruocchio ◽  
April M.H. Blakeslee
Keyword(s):  
Genetic Diversity ◽  
North Carolina ◽  
Population Structure ◽  
Gene Flow ◽  
Salinity Gradient ◽  
Western Atlantic ◽  
Widespread Species ◽  
Naked Goby ◽  
Gobiosoma Bosc ◽  
Scale Population

Many species of fish produce larvae that undergo a prolonged dispersal phase. However, evidence from a number of recent studies on demersal fishes suggests that the dispersal of propagules may not be strongly correlated with gene flow. Instead, other factors like larval behavior and the availability of preferred settlement habitat may be more important to maintaining population structure. We used an ecologically important benthic fish species, Gobiosoma bosc (naked goby), to investigate local and regional scale population structure and gene flow along a salinity gradient (∼3 ppt to ∼18 ppt) in two North Carolina estuaries. G. bosc is an abundant and geographically widespread species that requires complex but patchy microhabitat (e.g. oyster reefs, rubble, woody debris) for reproduction and refuge. We sequenced 155 fish from 10 sites, using a common barcoding gene (COI). We also included recent sequence data from GenBank to determine how North Carolina populations fit into the larger biogeographic understanding of this species. In North Carolina, we found a significant amount of gene flow within and between estuaries. Our analysis also showed high predicted genetic diversity based upon a large number of rare haplotypes found within many of our sampled populations. Moreover, we detected a number of new haplotypes in North Carolina that had not yet been observed in prior work. Sampling along a salinity gradient did not reveal any significant positive or negative correlations between salinity and genetic diversity, nor the proportion of singleton haplotypes, with the exception of a positive correlation between salinity standard deviation and genetic diversity. We also found evidence that an introduced European population of naked gobies may have originated from an Atlantic source population. Altogether, this system offers a compelling way to evaluate whether factors other than dispersal per se mediate recruitment in an estuarine-dependent species of fish with a larval dispersal phase. It also demonstrates the importance of exploring both smaller and larger scale population structure in marine organisms to better understand local and regional patterns of population connectivity and gene flow.

Status Update for Six Rare Crayfishes (Decapoda: Cambaridae) in Western North Carolina

2014 ◽  
Vol 130 (2) ◽  
pp. 25-39
Author(s):  
William T. Russ ◽  
Stephen J. Fraley
Keyword(s):  
North Carolina ◽  
Conservation Status ◽  
Limited Range ◽  
Distribution Data ◽  
Savannah River ◽  
Isolated Populations ◽  
River Drainage ◽  
Tennessee River ◽  
Western North Carolina ◽  
Little Tennessee River

Abstract From 2009–2012 detailed distribution data, information to update conservation status, and additional life history and habitat observations were obtained for six rare crayfishes in Western North Carolina. The Hiwassee Headwaters Crayfish, Cambarus (Puncticambarus) parrishi, continues to occupy a very limited range in Clay County, with most known occurrences from the Tusquitee Creek system. The Chauga Crayfish, C. (P.) chaugaensis, appears to be abundant throughout much of its range in the upper Savannah River Drainage, in Transylvania, Jackson, and Macon counties. The French Broad River Crayfish, C. (P.) reburrus, has declined in Madison and Buncombe counties, while populations in Transylvania County appear to have remained relatively stable. The Broad River Stream Crayfish, C. (Cambarus) lenati continues to occur primarily in the upper First Broad River drainage where it is common in some streams in Rutherford County. The Broad River Spiny Crayfish, C. (P.) spicatus is rare but continues to exist in two isolated populations: upper First Broad and North Pacolet river drainages. The Little Tennessee River Crayfish, C. (P.) georgiae continues to occupy Jackson and Macon counties where it is most abundant in the upper Little Tennessee River Drainage. No range expansions were observed for any of these crayfish species.

Genetic and phenotypic population structure of the Coenonympha tullia complex (Lepidoptera: Nymphalidae: Satyrinae) in California: no evidence for species boundaries

1988 ◽  
Vol 66 (12) ◽  
pp. 2751-2765 ◽  
Author(s):  
Adam H. Porter ◽  
Hansjürg Geiger
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Electrophoretic Analysis ◽  
Species Boundaries ◽  
Genetic Population ◽  
River Drainage ◽  
Migration Rates ◽  
The North ◽  
Northern Nevada ◽  
Very High

Decisions regarding species status of taxa showing geographic replacement are explicit hypotheses about population structure. The structure of 21 populations of the Coenonympha tullia group from northern California, southwestern Oregon, and northern Nevada was analyzed for evidence of reproductive isolation. These samples included five subspecies (california, eryngii, ampelos, eunomia, and mono) nominally placed in three species (california, ampelos, and ochracea). We found very high intra- and inter-population variability in the "diagnostic" wing pattern characters used by previous authors. There is evidence of intergradation between eryngii and eunomia in southwestern Oregon, and between california and ampelos in the eastern Feather River drainage in California. A complex cline involving California, eryngii, and ampelos occurs in the Pit River drainage of northeastern California. The taxon mono appears distinct, apparently because of an absence of Coenonympha populations in the expected mono–ampelos contact area. Electrophoretic analysis of the same 21 populations showed very high intrapopulation genetic variability (expected heterozygosity = 13.5–20.4%, percentage of polymorphic loci (most common allele < 99%) = 35.5–58.8%; 14 alleles at the locus for phosphoglucose isomerase (one population with 11 alleles)). However, interpopulation (geographic) variability was extremely low. Standardized genetic variance among populations (FST, using Wright's formulation) in contact zones indicates that gene flow is probably uninterrupted between the subspecies california, eryngii, ampelos, and eunomia. FST values for the isocitrate dehydrogenase locus indicate that present-day gene flow is probably unimportant in maintaining similarity between ampelos and mono. The genetic population structure is reminiscent of highly vagile colonizing species, but this may be largely historical, due to post-Pleistocene range changes rather than high present-day interpopulation migration rates. We conclude that all California populations are conspecific. Only the subspecies mono is clearly separated from the others, at the level 0.034 (Nei's unbiased distance), approximating that of weak subspecies in other taxa. The North American entities should all be provisionally classified as subspecies of the holarctic species tullia unless evidence is found to support their separation.

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