ABSTRACT
Illegal, Unreported and Unregulated fishing has had a major role in the overexploitation of global fish populations. In response, international regulations have been imposed and many fisheries have been 'eco-certified' by consumer organizations, but methods for independent control of catch certificates and eco-labels are urgently needed. Here we show that, by using gene-associated single nucleotide polymorphisms, individual marine fish can be assigned back to population of origin with unprecedented high levels of precision. By applying high differentiation single nucleotide polymorphism assays, in four commercial marine fish, on a pan-European scale, we find 93-100% of individuals could be correctly assigned to origin in policy-driven case studies. We show how case-targeted single nucleotide polymorphism assays can be created and forensically validated, using a centrally maintained and publicly available database. Our results demonstrate how application of gene-associated markers will likely revolutionize origin assignment and become highly valuable tools for fighting illegal fishing and mislabelling worldwide.
Subject(s)
Polymorphism, Single Nucleotide/genetics , Animals , Conservation of Natural Resources , Ecology , Fisheries , Fishes/geneticsABSTRACT
Tunga penetrans is a widely distributed sand flea, infecting men and domestic animals. It originated in South America, but it is now also endemic of Sub-Saharan Africa due to a recent accidental introduction. Previous genetic analyses indicated a very limited variability in the Ecuadorian populations; on the other hand, samples from Madagascar resulted to be genetically isolated. To better examine the genetic variability of T. penetrans, a wider sampling was analysed for mitochondrial (cytochrome oxidase II) and nuclear (ribosomal internal transcribed spacer [ITS] 2) DNA sequences. The mitochondrial marker confirms the low genetic variability, with few haplotypes characterizing the majority of individuals from different populations. Haplotype distribution is in agreement with a recent colonization of Africa and with a rapid spreading across this continent. Moreover, a consistent gene flow between the Pacific and Atlantic South American populations emerges, possibly due to human and/or animal cross-Andean dispersal. On the other hand, the ITS2 marker depicts a sharply diverging pattern with samples collected in Ecuador unequivocally distinguished from the Brazilian and African ones. On the whole, taking into account also the molecular features of the marker used, data here presented are better interpreted in the light of a high dispersal ability of T. penetrans, probably reducing the phylogeographic signal.
Subject(s)
Genetic Variation , Siphonaptera/genetics , Africa , Animals , Base Sequence , DNA, Ribosomal Spacer/genetics , Electron Transport Complex IV/genetics , Female , Mitochondria/enzymology , Phylogeny , South AmericaABSTRACT
We describe the ovicidal action of a 3.75% (w/v) sodium hypochlorite solution on the eggs of Aedes albopictus (Skuse). The effectiveness of this ovicide has also been confirmed by a field trial. On the basis of the data collected in the city of Bologna, Italy, we hypothesize a relationship between the numerical increase of the Ae. albopictus eggs laid and the reduced daily variation of the relative humidity, facilitating the possibility of planning ovicidal treatments.
Subject(s)
Aedes , Mosquito Control/methods , Sodium Hypochlorite , Animals , OvumABSTRACT
Wolbachia pipientis is an intracellular endosymbiont producing reproductive alterations in its hosts. This bacterium have been reported in many arthropods and nematodes. By PCR amplification and sequencing of the 16S rDNA and ftsZ genes we have identified a Wolbachia strain in the newly described sand-flea, Tunga trimamillata. Prevalence of this endosymbiont in the 26 individuals screened is equal to 35%. Sympatric and allopatric specimens of the related species Tunga penetrans were also analysed, but in contrast to literature data, Wolbachia appears absent in the presently analysed 24 specimens. Field studies evidence a female-biased sex-ratio in T. trimamillata, suggesting that Wolbachia may cause sex-ratio distortion in this species. By means of BLAST search and phylogenetic analysis we found that the Wolbachia strain from T. trimamillata pertains to the arthropod-infecting Wolbachia; this strain is highly differentiated from the Wolbachia strain of T. penetrans described in literature.
Subject(s)
DNA, Bacterial/analysis , DNA, Ribosomal/analysis , RNA, Ribosomal, 16S/genetics , Siphonaptera/microbiology , Wolbachia/isolation & purification , Animals , Bacterial Proteins/genetics , Cytoskeletal Proteins/genetics , Female , Genotype , Host-Parasite Interactions , Male , Molecular Sequence Data , Phenotype , Phylogeny , Polymerase Chain Reaction , Reproduction , Sequence Alignment , Sex Ratio , Siphonaptera/genetics , Siphonaptera/physiology , Symbiosis , Wolbachia/classification , Wolbachia/genetics , Wolbachia/physiologyABSTRACT
Electron microscopy of the cells of the follicle duct of Triops cancriformis shows that the follicular ducts are lined by a single-layered epithelium which also produces the eggshell material. The cytoplasm is rich in rough endoplasmic reticulum that synthesizes the eggshell material which subsequently aggregates into preformed vacuoles. Newly formed spheres of eggshell material are then excreted into the lumen. At the end of vitellogenesis the oocytes descend toward the longitudinal oviduct and pass through the eggshell material which fills the follicle ducts. The production of the eggshell and its chemical composition in some Phyllopoda are compared. The paper discusses the relationship between the eggshell construction and the reproductive biology of the population.
