To investigate phylogenetic relationships amongLeuciscusspecies occurring in Portuguese inland waters, the cytochromebgene was sequenced from representatives of the main rivers. This study supports ...the recognition of the species level forL. pyrenaicus,including populations from the southern Portuguese drainages (Tejo, Sado, and Guadiana drainages), and forL. carolitertii,including populations from the northern Portuguese drainages. The existence of two new species occurring in the extreme southwestern drainages of Mira and Arade is also suggested. The present results support the monophyly of the Mira and the Arade populations, as well as an early divergence of these two lineages. The present-day distribution ofLeuciscusspecies is seen as a consequence of Pliocene and Pleistocene events, such as river disjunctions and posterior confluence in epicontinental seas and river captures. A mixture of haplotypes was observed in the Mondego and the Tejo drainages, which could be a consequence of ancient river captures, with a possible mitochondrial DNA introgression in the Tejo drainage and a recent introduction by man in the Mondego drainage. The pattern of differentiation among mtDNA haplotypes and their geographic distribution is discussed in terms of evolutionary aspects.
Phylogenetic relationships between European cyprinids (Teleostei:Cypriniformes:Cyprinidae) were investigated by comparingcytochrome bgene sequences from 29 species, among which 20 were newly ...sequenced. Results were in general agreement with previous morphologically-based studies, but new interesting relationships were found. The classical barbelled/lacking barbels split is dubious. GenusLeuciscusappears paraphyletic. The phylogenetic location of some American cyprinid species was recovered; at least two distinct invasions of the New World are likely. Finally, the problem of intergeneric cyprinid hybrids is addressed. The genus rank for these interbreeding entities is supported and hybrids are seen as the consequence of a high genetic flexibility. This is the first molecularly based study of cyprinid diversity. It sheds light on the evolution and taxonomy of this major freshwater fish family.
The genetic variability of cultured stocks of common carp (
Cyprinus carpio) was studied using two types of genetic markers: allozymes and microsatellites. A comparative analysis was investigated ...between six strains from extensive aquaculture in two French regions (Dombes and Forez) and five strains from the Czech Republic stemming from artificial selection and maintained in the Research Center of Vodnany. Observed heterozygosity from allozyme data varied from 0.003 to 0.029 for French strains and was significantly lower than that observed for Czech strains, which varied from 0.026 to 0.058. The genetic variability of microsatellites for the whole data set was considerably higher than that for allozymes. The mean number of alleles per microsatellite locus was higher for French strains than for Czech strains (respectively, 6.2 and 4.2). Microsatellites are generally considered to be selectively neutral and the reduction of microsatellite allelic diversity in Czech strains could be related to a possible population bottleneck associated with breeding practice. However, the patterns of genetic variation for the two types of marker are possibly biased by the limited number of sampled individuals and must be confirmed in the future by more extensive studies. Significant differentiation between the strains was shown using
F statistics, whatever the tested groupings, and no obvious difference was detected between relationships inferred with the two types of genetic markers. A neighbour-joining analysis of genetic distances (chord distance of Cavalli-Sforza and Edwards Am. J. Hum. Genet 19 (1967) 233.) between strains showed that the topologies of the trees for microsatellites and allozymes were globally congruent. However, a more pronounced discrimination between the strains of the two countries was detected by the microsatellite markers which appeared more suitable to infer the effect of the geographical separation of the ancestral strains or different culture histories.
Phylogenetic relationships among Greek populations of the chub, Leuciscus cephalus, were investigated using 600 bp of the cytochrome b gene. The aim of this study was to test the assumption that the ...main difference in ichthyological composition between both sides of the Balkan Peninsula is directly linked to differences in the dispersion mechanisms used by fish in order to extend their distribution range. Phylogenetic and nested clade analyses clearly showed that populations in Greece are significantly differentiated. Greek populations were found to descend from three lineages in three geographical provinces: Western, Central, and Eastern Greece. The chub reached Western Greece at the beginning of the Pleistocene and Eastern Greece during the mid-Pleistocene. Chub dispersion occurred mainly by river confluence due to sea level lowering and river capture in Western Greece and sea dispersal with low-salinity conditions within the Aegean Sea in Eastern Greece. However, in Central Greece, the original mtDNA lineage has presumably been lost owing to a genetic introgression following a second invasion from the Danube during the final stage of the last glaciation. This study provides new elements for a better understanding of the composition of the contemporary ichthyofauna in Greece and highlights possible evolutionary mechanisms responsible for the high endemism rate in the Western Greek biogeographic province.
Les eaux résiduaires urbaines de la ville de Ouagadougou, ont été traitées par filtres plantés d'Androgopon gayanus et Vetiveria nigritana, deux poacées tropicales, afin d'apprécier leurs ...performances épuratoires. Les plants ont été repiqués à raison de 9 plants/m2 et deux tiges par trou dans des pilotes. Six mois après, ils ont été alimentés en eaux usées trois jours successifs par semaine et laissés au repos le reste du temps, avec une charge hydraulique de 60 L m-2 j-1. Les rendements sur la Demande Chimique en Oxygène (DCO) de 90 et 94% ont été observés respectivement pour le filtre planté d'A. gayanus et celui planté de V. nigritana, alors qu'en termes de Demande Biochimique en Oxygène de cinq jours (DBO5), les deux réacteurs s'équivalent avec des rendements moyens de 97,3 et 97,5%. Les abattements sur l'ammonium sont respectivement de 96 et 97% pour les deux filtres. S'agissant du phosphore, le pilote planté d'A. gayanus a donné un abattement moyen sur les orthophosphates de 75% tandis qu'il est de 67% avec V. Nigritana. La forte évapotranspiration dans la zone d'étude explique les faibles débits restitués et l'augmentation de la conductivité de 68% pour le premier et de 28% pour le second.
Geographical variation of cytochrome b mitochondrial DNA (mtDNA) in chub (Leuciscus cephalus L.) was analysed in 31 samples from 20 different river basins in the Balkan Peninsula and Danube ...catchment. Multivariate methods of ordination were used to analyse variation of the data sets. The results were interpreted in the context of the proposed ichthyogcographic districts separating the Balkan Peninsula into two main ichthyogeographic divisions (Eastern Greece/Ponto-Acgcan and Western Greece/South Adriatic-Ionian). Boundary detection supported these two ichthyogeographic districts for L. cephalus, revealing a boundary that ran from north to south through the Balkan Peninsula and the middle of Greece. The results also revealed the existence of a third division in Central Greece. The results of ordination techniques on homogeneous zones and analysis of the molecular variance confirmed the results obtained in studying local variability (boundaries). They also allowed us to test the existence of possible subdivisions proposed by different authors inside the two main ichthyogeographic districts. These subdivisions were not supported. The multivariate methods used in this study allowed us to propose a coherent picture of chub ichthyogeographic districts in terms of boundary detection and maximal autocorrelation between populations and to explain the patterns of chub mtDNA variation. A complete interpretation of results concerning L. cephalus requires careful consideration of both boundary analysis and autocorrelative approach. Results from an the autocorrclativc approach alone could lead to substantial misinterpretations.
Geographical variation of cytochromebmitochondrial DNA (mtDNA) in chub (Leuciscus cephalusL.) was analysed in 31 samples from 20 different river basins in the Balkan Peninsula and Danube catchment. ...Multivariate methods of ordination were used to analyse variation of the data sets. The results were interpreted in the context of the proposed ichthyogeographic districts separating the Balkan Peninsula into two main ichthyogeographic divisions (Eastern Greece/Ponto-Aegean and Western Greece/South Adriatic-Ionian). Boundary detection supported these two ichthyogeographic districts forL. cephalus, revealing a boundary that ran from north to south through the Balkan Peninsula and the middle of Greece. The results also revealed the existence of a third division in Central Greece. The results of ordination techniques on homogeneous zones and analysis of the molecular variance confirmed the results obtained in studying local variability (boundaries). They also allowed us to test the existence of possible subdivisions proposed by different authors inside the two main ichthyogeographic districts. These subdivisions were not supported. The multivariate methods used in this study allowed us to propose a coherent picture of chub ichthyogeographic districts in terms of boundary detection and maximal autocorrelation between populations and to explain the patterns of chub mtDNA variation. A complete interpretation of results concerningL. cephalusrequires careful consideration of both boundary analysis and autocorrelative approach. Results from an the autocorrelative approach alone could lead to substantial misinterpretations.
The phylogenetic and systematic relationships among 12 populations of Greek chub (
Leuciscus cephalusL.) were investigated using RFLP analysis of two PCR-amplified mtDNA segments (D-loop and ...cytochrome b). Three out of eight, and nine out of ten restriction enzymes were polymorphic for D-loop and cytochrome b, respectively. Twenty-one different haplotypes were detected. Estimated nucleotide sequence divergence among the 21 genotypes ranged from 0.313 to 6.79%; the mean value of sequence divergence among populations was 3.421±0.00%. The calculated N
ST value of 0.94, indicates high interpopulation diversity. Dendrograms based on haplotypes as well as those of populations, support the previous recognition of different subspecies, but these mtDNA data are not concordant with previous allozyme data among these fish. Our results suggest that to clarify phylogenetic relationships multiple genetic systems need to be examined.
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