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Unique Alleles (unique + allele)

Distribution by Scientific Domains

Life Sciences	80%

Selected Abstracts

Invasion genetics of the Eurasian round goby in North America: tracing sources and spread patterns

MOLECULAR ECOLOGY, Issue 1 2009
JOSHUA E. BROWN
Abstract The Eurasian round goby Neogobius melanostomus (Apollonia melanostoma) invaded the North American Great Lakes in 1990 through ballast water, spread rapidly, and now is widely distributed and moving through adjacent tributaries. We analyse its genetic diversity and divergence patterns among 25 North American (N = 744) and 22 Eurasian (N = 414) locations using mitochondrial DNA cytochrome b gene sequences and seven nuclear microsatellite loci in order to: (i) identify the invasion's founding source(s), (ii) test for founder effects, (iii) evaluate whether the invasive range is genetically heterogeneous, and (iv) determine whether fringe and central areas differ in genetic diversity. Tests include FST analogues, neighbour-joining trees, haplotype networks, Bayesian assignment, Monmonier barrier analysis, and three-dimensional factorial correspondence analysis. We recovered 13 cytochrome b haplotypes and 232 microsatellite alleles in North America and compared these to variation we previously described across Eurasia. Results show: (i) the southern Dnieper River population was the primary Eurasian donor source for the round goby's invasion of North America, likely supplemented by some alleles from the Dniester and Southern Bug rivers, (ii) the overall invasion has high genetic diversity and experienced no founder effect, (iii) there is significant genetic structuring across North America, and (iv) some expansion areas show reduced numbers of alleles, whereas others appear to reflect secondary colonization. Sampling sites in Lake Huron's Saginaw Bay and Lake Ontario significantly differ from all others, having unique alleles that apparently originated from separate introductions. Substantial genetic variation, multiple founding sources, large number of propagules, and population structure thus likely aided the goby's ecological success. [source]

Microsatellite variation within and among North American lineages of Phragmites australis

MOLECULAR ECOLOGY, Issue 7 2003
K. Saltonstall
Abstract Over the past century, the spread of the common reed (Phragmites australis) has had a dramatic impact on wetland communities across North America. Although native populations of Phragmites persist, introduced invasive populations have dominated many sites and it is not clear if the two types can interbreed. This study compares patterns of differentiation in 10 microsatellite loci among North American and European Phragmites individuals with results obtained from sequencing of noncoding chloroplast DNA. Three population lineages (native, introduced and Gulf Coast) were previously identified in North America from chloroplast DNA and similar structuring was found in the nuclear genome. Each lineage was distinguished by unique alleles and allele combinations and the introduced lineage was closely related to its hypothesized source population in Europe. Size homoplasy and diagnostic base substitutions distinguishing lineages were evident at several loci, further emphasizing that native, introduced and Gulf Coast North American Phragmites lineages are genetically distinct. Gene flow between lineages was low and invasive introduced populations do not represent a hybrid population type. [source]

Population structure of Atlantic salmon (Salmo salar L.): a range-wide perspective from microsatellite DNA variation

MOLECULAR ECOLOGY, Issue 4 2001
T. L. King
Abstract Atlantic salmon (n = 1682) from 27 anadromous river populations and two nonanadromous strains ranging from south-central Maine, USA to northern Spain were genotyped at 12 microsatellite DNA loci. This suite of moderate to highly polymorphic loci revealed 266 alleles (5,37/locus) range-wide. Statistically significant allelic and genotypic heterogeneity was observed across loci between all but one pairwise comparison. Significant isolation by distance was found within and between North American and European populations, indicating reduced gene flow at all geographical scales examined. North American Atlantic salmon populations had fewer alleles, fewer unique alleles (though at a higher frequency) and a shallower phylogenetic structure than European Atlantic salmon populations. We believe these characteristics result from the differing glacial histories of the two continents, as the North American range of Atlantic salmon was glaciated more recently and more uniformly than the European range. Genotypic assignment tests based on maximum-likelihood provided 100% correct classification to continent of origin and averaged nearly 83% correct classification to province of origin across continents. This multilocus method, which may be enhanced with additional polymorphic loci, provides fishery managers the highest degree of correct assignment to management unit of any technique currently available. [source]

Eleven new microsatellites for hop (Humulus lupulus L.)

MOLECULAR ECOLOGY RESOURCES, Issue 4 2002
J. Jak
Abstract We present a new set of 11 polymorphic microsatellite primer sequences for use with Humulus lupulus. Microsatellite-enriched libraries for GAn and GTn types of repeats were produced. Sequencing of 72 clones revealed 42 unique inserts containing microsatellites, out of which 19 primer pairs were designed and microsatellite amplification was tested on 39 wild hops and cultivars. Eleven primer pairs showed single locus amplification with 2,13 alleles, average 7.2, of which 17 unique alleles were discovered. One primer pair amplified too strong stutter bands, one locus was monomorphic and multilocus amplification was obtained with the remaining six primer pairs. [source]

Population genetic structure of sea cucumber, Stichopus japonicus in Korea using microsatellite markers

AQUACULTURE RESEARCH, Issue 10 2008
Mi-Jung Kim
Abstract Sea cucumber (Stichopus japonicus) is a commercially valuable species in Korea. We examined the genetic characteristics of sea cucumber populations in Korea using microsatellite markers. A total of 144 sea cucumbers from five populations were typed for nine polymorphic microsatellite loci. A total of 139 different alleles were found over all loci and many alleles were unique. The average number of allele per locus ranged from 6 to 18.4. The average observed and expected heterozygosities ranged from 0.532 to 0.626 and from 0.719 to 0.789 respectively. All populations showed significant departure from Hardy,Weinberg equilibrium at almost all loci except one (Psj2409). This deviation was in the direction of heterozygote deficit. A phylogenetic tree revealed two distinct clusters. One cluster was formed by the eastern sea population. A second cluster consisted of the subpopulations of the western and southern sea populations. The eastern sea population showed genetic differences such as a larger number of alleles per locus, a larger number of unique alleles and a smaller number of the most common alleles, suggesting a higher genetic diversity in this population. These results provide basic information on natural population genetic structure of S. japonicus in Korea. [source]