Daphnia pulex, the crustacean with the first sequenced genome, is an important organism that has been widely used in ecological and toxicological research. MicroRNAs (miRNAs) are 21-25 nucleotide small non-coding RNAs that are involved in a myriad of physiological processes. In this research, we predicted 75 D. pulex miRNAs by sequence homology and secondary structure identification from the fu...

Daphnia p&x (Crustacea, Cladocera) was fed the blue-green algae (Cyanophyceae) Anacystis nidulans, Synechococcus elongata, S. cedrorum, Merismopedia sp., Anabaena flosaquae, Synechocystis sp., and Gloeocapsa alpicola. The green algae ( Chlorophyceae) Ankistrodesmus falcatus and Chlorella uulgaris were used for comparison. Direct observations were made of D. pulex feeding in depression slides fi...

considering the crucial importance of daphnia species in aquaculture, in particular for artificially- cultured sturgeon fry, a comprehensive study on the hatching requirements of their diapausing eggs seemed to be inevitable in order to obtain the ideal hatching technique. to do so, the ephippial eggs were collected from live food ponds in the cultivation and breeding centre of gorgan and after...

Hybridization plays a potentially important role in the origin of obligate parthenogenesis (OP) in many organisms. However, it remains controversial whether hybridization directly triggers the transition from sexual reproduction to obligate asexuality or a hybrid genetic background enables asexual species to persist. Furthermore, we know little about the specific genetic elements from the diver...

Improvements in sequencing technology over the past 5 years are leading to routine application of shotgun sequencing in the fields of ecology and evolution. However, the theory to estimate evolutionary parameters from these data is still being worked out. Here we present an extension and implementation of part of this theory, mlRho. This program can efficiently compute the following three maxim...

In Daphnia (Cladocera, Crustacea), parthenogenetic reproduction alternates with sexual reproduction. Individuals of both sexes that belong to the same parthenogenetic line are genetically identical, and their sex is determined by the environment. Previously, non-male producing (NMP) genotypes have been described in species of the Daphnia pulex group. Such genotypes can only persist through phas...

We describe the first genetic linkage map for Daphnia pulex using 185 microsatellite markers, including 115 new markers reported in this study. Our approach was to study the segregation of polymorphisms in 129 F2 progeny of one F1 hybrid obtained by crossing two genetically divergent lineages of Daphnia isolated from two Oregon populations. The map spanned 1206 Kosambi cM and had an average int...

Phenotypic plasticity is the ability held in many organisms to produce different phenotypes with a given genome in response to environmental stimuli, such as temperature, nutrition and various biological interactions. It seems likely that environmental signals induce a variety of mechanistic responses that influence ontogenetic processes. Inducible defenses, in which prey animals alter their mo...