Search publications of the members of the Royal Belgian institute of natural Sciences
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Effect of pH on the biological availability of copper to the brine shrimp Artemia franciscana
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Enzyme variation in Haplochromine cichlid fishes from Lake Victoria
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Etude préliminaire des effets de la fragmentation des forêts sur la similarité des habitats et leurs richesses en espèces de rongeurs (Masako, RD Congo).
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Evaluation of microwave heating digestion and graphite furnace atomic absorption spectrometry with continuum source background correction for the determination of iron, copper and cadmium in brine shrimp
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Evolution of the tribe Tropheini from Lake Tanganyika: synchronized explosive speciation producing multiple evolutionary parallelism
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Evolutionary relationships among narrow-headed rats (genus Stenocephalemys, muridae, rodentia) inferred from complete cytochrome b gene sequences
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Extensive Introgression among Ancestral mtDNA Lineages: Phylogenetic Relationships of the Utaka within the Lake Malawi Cichlid Flock.
- We present a comprehensive phylogenetic analysis of the Utaka, an informal taxonomic group of cichlid species from Lake Malawi. We analyse both nuclear and mtDNA data from five Utaka species representing two (Copadichromis and Mchenga) of the three genera within Utaka. Within three of the five analysed species we find two very divergent mtDNA lineages. These lineages are widespread and occur sympatrically in conspecific individuals in different areas throughout the lake. In a broader taxonomic context including representatives of the main groups within the Lake Malawi cichlid fauna, we find that one of these lineages clusters within the non-Mbuna mtDNA clade, while the other forms a separate clade stemming from the base of the Malawian cichlid radiation. This second mtDNA lineage was only found in Utaka individuals, mostly within Copadichromis sp. "virginalis kajose" specimens. The nuclear genes analysed, on the other hand, did not show traces of divergence within each species. We suggest that the discrepancy between the mtDNA and the nuclear DNA signatures is best explained by a past hybridisation event by which the mtDNA of another species introgressed into the ancestral Copadichromis sp. "virginalis kajose" gene pool.
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From conical to spatulate: Intra-and interspecific changes in tooth shape in closely related cichlids (Teleostei; Cichlidae: Eretmodini)
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General protein patterns of muscle homogenates of some Lake Victoria haplochromines (Pisces: Cichlidae)
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Genetic diversity and condition factor: a significant relationship in Flemish but not in German populations of the European bullhead (Cottus gobio L.).
- Although evidence of associations between genetic diversity and fitness in wild species has been published, the lack of a comprehensive review across species and the existence of contradictory results have led to scepticism remaining about its existence and importance in natural populations. In this study, the relationship between genetic diversity at six microsatellite loci and condition factor (a fitness related trait) was investigated at the population level in both Flemish and German populations of the European bullhead (Cottus gobio). A significant positive correlation was observed between genetic variability and the condition factor in Flemish but not in German bullhead populations. Environmental conditions such as conductivity of the water seemed more important in determining the condition factor of these latter populations. Regardless of the underlying mechanism(s) responsible for the different relationships, the results of this study suggest that both genetic and environmental variables can influence condition factor of bullhead populations.
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Genetics and speciation in African lacustrine cichlids
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Hemoglobin heterogeneity and the oxygen affinity of the hemolysate of some Victoria cichlids.
- The hemoglobin patterns of ten cichlid species from Lake Victoria were characterized by polyacrylamide gel electrophoresis. In all tested species the hemoglobin bands display the same electrophoretic mobility. Oxygen equilibria of the purified hemoglobin solution of five species were determined under standardized conditions (pH 7.4 at 20 degrees C). The analysed hemolysates have a relatively high oxygen affinity and for all the tested species the Hill coefficient approached unity. The effect of temperature on the oxygen affinity of Haplochormis "velvet black" hemolysate was determined at 20, 25, 30 and 35 degrees C. The obtained results (delta H value-68 kJ/mol) at pH 8.2 is comparable with earlier published results for other African and South American Cichlidae. The Bohr effect (phi = delta log P50/delta pH = -0.18 between pH 6.6-7.4 at 25 degrees C) proved to be lower than so far reported in other Cichlidae.
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High microsatellite genetic variability of the stone loach, Barbatula barbatula, in anthropogenically disturbed watercourses
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Historical metal pollution in natural gudgeon populations: Inferences from allozyme, microsatellite and condition factor analysis.
- This study presents the results of a microsatellite and allozyme analysis on natural populations of the gudgeon (Gobio gobio) located in a pollution gradient of cadmium and zinc. Differences among contaminated and reference populations were observed at 2 allozyme loci, as well as a relationship between the fish condition factor and glucose-6-phosphate dehydrogenase genotypes, the locus that showed the largest difference in allele frequencies. The microsatellite data partly confirmed the differentiation pattern that was revealed by the allozyme survey. Our data further suggest that at least 2 microsatellite loci may be affected by natural selection. We thus illustrate that both microsatellite and allozyme loci do not necessarily behave as selectively neutral markers in polluted populations. Estimates of population differentiation can therefore be significantly different depending on which loci are being studied. Finally, these results are discussed in the light of the conservation unit concept, because microsatellites are often used to assess genetic variation in endangered natural populations and to propose measures for conservation or management.
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In situ experiments on the effects of increased sediment loads on littoral rocky shore communities in Lake Tanganyika, East Africa
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In the Royal Belgian Institute of Natural Sciences, Molecular techniques are used to study evolution.pdf
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Integration of molecular and traditional taxonomic concepts and procedures.pdf
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Isolation and characterization of polymorphic microsatellite loci in the gudgeon, Gobio gobio (Cyprinidae)
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Low genetic and morphometric intraspecific divergence in peripheral copadichromis populations (perciformes: cichlidae) in the lake Malawi basin.
- Peripheral isolated populations may undergo rapid divergence from the main population due to various factors such as a bottleneck or a founder effect followed by genetic drift or local selection pressures. Recent populations of two economically important Copadichromis species in Lake Malombe, a satellite lake of Lake Malawi, were neither genetically nor morphometrically distinct from their source populations in the main lake. Evidence was found for a founder effect which had a different impact on the genetic composition of the two species. In addition, the increased fishing pressure in Lake Malombe may have led to a reduction of the body sizes of both species.
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Metabolic rate, hypoxia tolerance and aquatic surface respiration of some lacustrine and riverine African cichlid fishes (Pisces: Cichlidae)
