Morphological Differentiation, Mitochondrial and Nuclear DNA Variability Between Geographically Distant Populations of Daphnia galeata and Daphnia cucullata (Anomopoda, Daphniidae)

• Main Authors: Elena I. Zuykova, Nickolai A. Bochkarev, Anna S. Semenova, Alexey V. Katokhin
• Format: Article
• Language: English
• Published: Siberian Federal University 2010-12-01
• Series: Журнал Сибирского федерального университета: Серия Биология
• Subjects: Daphnia galeata; Daphnia cucullata; morphological variation; mitochondrial DNA; nuclear DNA; genetic divergence
• Online Access: http://elib.sfu-kras.ru/bitstream/2311/2250/1/Zuykova.pdf

Although members of genus Daphnia (Anomopoda, Daphniidae) are the most common water invertebrates and are considered as model organisms for many taxonomic, ecological and evolutionary studies their systematics remains unresolved. Here, morphological differentiation and genetic polymorphism between the geographically distant populations of the sister species Daphnia galeata Sars, 1864 and Daphnia cucullata Sars, 1862 in the Curonian Lagoon, a large shallow freshwater lagoon of the Baltic Sea (Russia, Kaliningrad Oblast) and Novosibirsk Reservoir (Russia, Novosibirsk Oblast) are presented. The divergence between species and their populations was analyzed based on traditional morphological traits and a large set of morphometric traits describing the body shape. The traits describing the shape of head and helmet, and spine were the most variable morphological characters. Phylogenetic relationships between species and populations were constructed based on variation in mitochondrial 16S and 12S rRNA genes and nuclear ITS2 rDNA sequences. The mitochondrial DNA divergence between D. galeata and D. cucullata species was significant and reflected their monophyletic origin, whereas intraspecific genetic distances are estimated as insignificant.