1022-7954/03/3903- $25.00 © 2003 MAIK “Nauka /Interperiodica” 0356 Russian Journal of Genetics, Vol. 39, No. 3, 2003, pp. 356–358. Translated from Genetika, Vol. 39, No. 3, 2003, pp. 439–441. Original Russian Text Copyright © 2003 by Bychek, Müller. To date, the problem of the invasion of alien or exotic species to the territories of different countries attracts growing attention. The importance of this prob- lem needs no special comments. The realization of the significance of this phenomenon resulted in the forma- tion of working groups focused on the studies of the estuaries and marine ecosystems of the Baltic region and Caspian basin. Also, the international cooperation in the field of management of the ballast waters, etc., is being developed. The urgency of this problem for Rus- sia can be judged from the recently organized Ameri- can–Russian symposium on invasive or invading spe- cies (Borok, Russia, August 27–31, 2001). In this respect, not only studies of the biology of newly invaded species and the ecological consequences of their invasion, but also elucidation of their natural distribution ranges and their migration routes become urgent. It should be mentioned that for a number of aquatic invertebrate groups the problem of species identifica- tion still remains a challenge. This primarily concerns morphological diagnostics of some Daphnia species. Polymorphism of the members of Daphnia longispina complex is well known. According to Korovchinskii [1], classification of the forms of plastic species such as Daphnia longispina, D. galeata, and D. hyalina is rather questionable, and there are no unambiguous cri- teria for their isolation. This opinion is shared by Glagolev [2], who attributes the above species to the longispina group and considers the species isolation within this group as provisional. Nevertheless, analysis of Daphnia individuals from different isolated pools resulted in establishing some reasonable morphological differences between the above species [3]. This, how- ever, does not solve the problem on a wider scale. The published list of aquatic organisms inhabit- ing the Volga River [4] contains eight Daphnia spe- cies. D. galeata is not mentioned, although a number of generally accepted diagnostic features indicate its pres- ence. For these reasons, the present study was focused on the genetic diagnostics of some frequent Daphnia species from the Volga River. Parthenogenetic clones were bred in laboratory con- ditions from the round-headed (A) and helmeted (B) Daphnia females collected in the near Damp pool of the Kuibyshev reservoir and in the upper part of the Saratov reservoir on May 21 and June 18, 1998.* Analogous clones were obtained from the D. cucullata G.O. Sars (C) individuals and from a round-headed female (D), respectively caught on June 18 and August 30, 1998, in the Kuibyshev reservoir. Animals were fixed in ethanol, and total DNA was extracted from each clone by incu- bating in the H3 buffer (10 mM Tris–HCl, pH 8.3 at 25°C; 0.05 M KCl; 0.005% NP-40; Replithern Reac- tion Buffer, Biozym), containing 15 μg of proteinase K. The volume of the H3 buffer depended on the number of the animals in the sample [5]. The DNA extracts obtained were used for cloning performed by use of polymerase chain reaction (PCR). PCR fragments were amplified using the mitochondrial DNA (mtDNA)(16S rRNA) specific primers, S1 (5'- CGGCCGCCTGTTTATCAAAAACAT-3') and S2 (5'- GGAGCTCCGGTTTGAACTCAGAT-3'), which were the modified universal primers, LR-J-12887 and LR-N- 13398 [6]. The reaction conditions were 3 min at 93°C for denaturation followed by 35 cycles of 92°C for 45 s; 55°C for 45 s; 72°C for 44 s; and a final incubation of 7 min at 72°C. Molecular Genetic Diagnostics of Some Daphnia Species (Crustacea, Cladocera) from the Volga River E. A. Bychek 1 and J. Müller 2 1 Institute of Ecology of the Volga Basin, Russian Academy of Sciences, Togliatti, 445003 Russia; fax: (8482)489504; e-mail: bychek@tlt.volga.ru 2 Department of Population Biology, Zoological Institute University of Mainz, Mainz, 55099 Germany; fax: +49+6131 3923731; e-mail: jakob@oekologie.biologie.uni-mainz.de Received March 1, 2002; in final form, August 13, 2002 Abstract—Population genetic structure of the widespread Daphnia species from Kuibyshev and Saratov res- ervoirs was examined using RAPD–PCR technique with four mitochondrial DNA (16S rRNA) specific primers. One of the Daphnia clones examined from the Volga region appeared to be conspecific to the North American Daphnia galeata, while another clone was most likely a hybrid between D. galeata and D. cucullata. SHORT COMMUNICATIONS * According to the diagnostic morphological features suggested by Manuilova [7], these Daphnia females from the Volga River are attributed to D. longispina O.F. Müller.