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  • allozymes  (7)
  • Springer  (7)
  • American Association for the Advancement of Science
  • American Institute of Physics (AIP)
  • American Physical Society
  • Annual Reviews
  • Institute of Physics
  • International Union of Crystallography
  • 2000-2004  (7)
  • 1955-1959
  • 1945-1949
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  • Springer  (7)
  • American Association for the Advancement of Science
  • American Institute of Physics (AIP)
  • American Physical Society
  • Annual Reviews
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  • 1
    Electronic Resource
    Electronic Resource
    Genetic Distances Among North American, British, and West African House Fly Populations (Musca domestica L.) (2000)
    Springer
    Biochemical genetics 38 (2000), S. 275-284 
    Details
    ISSN: 1573-4927
    Keywords: Musca domestica ; allozymes ; mtDNA ; gene flow ; population genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Allozyme and mitochondrial gene diversities were estimated in house flies, Musca domestica L. (Diptera: Muscidae), sampled in Iowa, USA; Berkshire, England; and Kudang, The Gambia. Comparison of genomic allele frequencies among the three populations indicated small differences between the English and American samples but very large distances between English or American and the African. The F ST statistic was 0.65 ± 0.09 for allozymes. Pairwise F ST was 0.14 between the English and the American samples; F ST was 0.65 between the African population and the English and American. Mitochondrial variation in the same flies was assessed by SSCP methods which revealed nine haplotypes, none of which were shared in common. F ST was 0.637 for the mitochondrial haplotypes. The research indicates greatly restricted gene flow between Africa and the temperate regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1002010632647
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  • 2
    Electronic Resource
    Electronic Resource
    Allozymic variation and relationships withinViola subsectionViola (Violaceae) (2000)
    Springer
    Plant systematics and evolution 223 (2000), S. 29-57 
    Details
    ISSN: 1615-6110
    Keywords: Violaceae ; Viola ; allozymes ; introgression ; reticulate evolution ; hybrid speciation ; paleopolyploidy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Allozyme markers from ten European taxa ofViola subsectionViola suggest that this group is allotetraploid, based on x = 5. All taxa had distinct multilocus phenotypes exceptV. alba subspp.alba andscotophylla, which were identical and different from subsp.dehnhardtii. Variation was consistently higher in Mediterranean populations than in North European ones. Hybridisation seems extensive but putative F1 hybrids were distinctly less fertile than the parental species. Nevertheless, increased fertility in later-generation hybrids and shared band patterns among taxa indicate an important role of hybridisation and introgression in past and present evolution within the subsection. The octoploidV. ambigua shows affinity toV. hirta (tetraploid). The octoploidV. suavis probably originated fromV. pyrenaica and other unidentified tetraploids, and high variability suggests polytopy or even polyphyly. The stoloniferous condition (seriesFlagellatae) seems to be primitive in the subsection but the reduction of stolons (seriesEflagellatae) may have originated multiple times.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985325
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  • 3
    Electronic Resource
    Electronic Resource
    The use of allozymes at three life stages influences genetic variation analysis and clustering in Cicer arietinum germplasm collections (2000)
    Springer
    Euphytica 112 (2000), S. 109-115 
    Details
    ISSN: 1573-5060
    Keywords: allozymes ; Bangladesh ; chickpea ; Cicer arietinum ; conservation ; genetics ; germplasm ; populations ; variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Levels of genetic variation using 6 enzyme systems for a total of 11 interpretable loci were examined in chickpea (Cicer arietinum) originating from 9locations in Bangladesh. The measurement of genetic variation at enzyme loci was carried out on the seed embryo, on the early leaves of seedlings and on the mature leaves at the vegetative stage. A total of 592individuals, including 240 seeds, 200 seedlings and152 mature leaves were investigated. Using electrophoretic data, chickpea was found to express higher percentages of polymorphic loci at the seed stage (36–64%) than at seedling (22–56%) or the vegetative stage (11–44%). The proportion of mean number of alleles and the average mean observed heterozygosity also were higher at the seed stage when compared to the seedling and vegetative stages. Unique alleles were absent, and only differences infrequencies could be noticed. Positive values of the fixation index were noted for pgm-1 and 6pg-1 for all stages and in both mnr loci for the seed embryo's. A trend towards lower genetic distances of all possible pairs of populations could be observed when comparing those of seed embryo's with seedlings or mature leaves. This trend was even more pronounced when pooling the data of 9 populations into their 3regions. Slight differences in genetic distances caused a separative clustering of population 3 at seed embryo, of population 2 at seedling and of population5 at vegetative stages. It is suggested that careful examination of enzyme polymorphisms at different developmental stages is a prerequisite before drawing conclusions on the genetic distance between germplasm collections from different origins since small differences in the data entry for clustering results in ties that may affect tree topologies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003851113039
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  • 4
    Electronic Resource
    Electronic Resource
    Genetic differentiation in Chilean hake Merluccius gayi gayi (Pisces: Merlucciidae) (2000)
    Springer
    Hydrobiologia 420 (2000), S. 49-54 
    Details
    ISSN: 1573-5117
    Keywords: allozymes ; stock ; Pacific Ocean ; Chile ; electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genetic structure of Chilean hake Merluccius gayi gayi, was analyzed using starch gel protein electrophoresis. Samples were collected from four localities along the coast off Chile. A total of 1500 specimens sampled from Coquimbo, San Antonio, Talcahuano and Puerto Montt were used in the study. Genetic information was obtained for six allozyme loci Pgi-1, Pgi-2, Pgm, Idh-1, Idh-2 and Aat. The results of the analysis showed no significant allelic differences among samples from various localities, with an average FST value of 0.007 for all loci and samples. A heterogeneity test for all loci and specimens from the four localities showed only two significant values. Thus, Chilean hake populations along the coast of Chile appear to be genetically homogeneous.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003925402062
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of copper on the fitness of the Chilean scallop Argopecten purpuratus (Mollusca: Bivalvia) (2000)
    Springer
    Hydrobiologia 420 (2000), S. 185-189 
    Details
    ISSN: 1573-5117
    Keywords: allozymes ; toxicity ; mollusks ; pollution ; heterozygosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Exposure to high concentrations of metals can affect populations and individuals at morphological, physiological, biochemical or genetic levels. Metal pollution is a source of environmental stress that can have deleterious effects on organisms and generate selective pressure upon populations. This work attempts to establish whether concentrations of copper, above physiological requirements, can affect the genetic structure of a cohort of Chilean scallop Argopecten purpuratus. Following the determination of LC50 for 96 h experiments, other acute toxicity tests were carried out, exposing the juveniles to solutions of 150 ppb copper for 120 h. Dead, surviving and control individuals from these bioassays were genetically characterized for five polymorphic loci, Isocitrate dehydrogenase (Idh), Octopine dehydrogenase (Ocdh), Phosphogluconate dehydrogenase (Pgd), Leucine aminopeptidase (Lap) and Phosphoglucose isomerase (Pgi). Results showed no significant differences in allele and genotypic frequencies between surviving and dead individuals, although for the same groups significant differences were found in estimated mean heterozygosity. Pgi and Ocdh showed significantly different heterozygosity values for dead and surviving individuals. A positive relationship between multilocus heterozygosity and survival was found for young A. purpuratus exposed to high copper concentrations; thus, we found evidence of a differential response to exposure to high copper concentrations, related to degree of heterozygosity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003947407939
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  • 6
    Electronic Resource
    Electronic Resource
    Genetic population structure of the swimming crab Callinectes danae (Crustacea: Decapoda) in southern Brazil (2000)
    Springer
    Hydrobiologia 420 (2000), S. 203-210 
    Details
    ISSN: 1573-5117
    Keywords: Portunidae ; population genetics ; gene flow ; allozymes ; estuarine retention
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The population genetic structure of the swimming crab Callinectes danae (Crustacea, Portunidae) was studied by allozyme electrophoresis along the southern coast of Brazil (Santa Catarina and Rio Grande do Sul States). The biology of C. danae is poorly known, but some studies suggest that this species depends on estuaries for reproduction and for completing its life cycle, using them as recruitment sites and nursery grounds. If estuarine retention is an important process acting in favour of the recruitment of local populations, we should expect restriction of gene flow among populations inhabiting different estuaries. Therefore, our aim was to establish whether gene flow between populations of C. danaefrom different estuaries was restricted. Samples were collected in four estuaries: São Francisco do Sul, Laguna (Santa Catarina), Patos Lagoon and Chuí Stream (Rio Grande do Sul). Eleven loci were resolved. Contingency table tests (χ2 and G) showed significant differences (P≤0.05) between pair-wise subpopulation comparisons. The estimated F ST was θ=0.065±0.019, suggesting a moderate structuring of C. danae populations. No relationship was found for the number of migrants between pairs of subpopulations and the geographic distance separating them (P= 0.292; r 2= 0.269). Nevertheless, UPGMA analysis clustered together those estuaries separated by less than 250 km. Low adult migration, the requirement of estuaries as reproductive areas, recruitment sites and nursery grounds for juveniles, together with larval and post-larval retention processes, are discussed in the context of their importance in preventing panmixia among subpopulations inhabiting different estuaries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003992630229
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  • 7
    Electronic Resource
    Electronic Resource
    Genetic divergence and larval dispersal in two spider crabs (Crustacea: Decapoda) (2000)
    Springer
    Hydrobiologia 420 (2000), S. 211-219 
    Details
    ISSN: 1573-5117
    Keywords: Crustacea ; Majidae ; allozymes ; gene flow ; larval dispersal ; Inachus ; Hyas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spider crabs Inachus dorsettensis (Pennant) and Hyas coarctatus Leach are widespread in subtidal areas of muddy sand or gravel around western Europe. Both species have a life cycle with an obligatory planktonic larval phase of several weeks, which might be expected to cause widespread larval dispersal and consequent genetic homogeneity over considerable distances. However, earlier work on both taxa has indicated differences in growth pattern between populations separated by tens of kilometres. This study was undertaken to determine whether these differences were purely environmental or whether, despite the short distances involved, differences may have a genetic basis. A study of gene frequencies, as indicated by allozymes in samples of adults collected off the Isle of Man (northern Irish Sea), indicates significant genetic differentiation between populations over a geographical distance of only about 40 km in both Inachus dorsettensis (θ = 0.086 ± 0.048) and Hyas coarctatus (θ = 0.023 ± 0.017). Variability measures differed between species, showing I. dorsettensis to have a mean number of alleles per locus of 2.5–2.6 and a range of gene diversity of 0.216–0.241, while H. coarctatus showed lower values of mean number of alleles (1.9–2.0) and a range of gene diversity from 0.122 to 0.124. Given the high expected larval mobility of the two species the results are most surprising. Possible explanations are discussed in relation to population discontinuities and patterns of larval drift.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003905115208
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