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DIFFERENTIATION AND SYSTEMATICS IN THE LONG-TAILED GROUND SQUIRREL, SPERMOPHILUS UNDULATUS (SCIURIDAE, RODENTIA). Marina V. Tsvirka, Vladimir P. Korablev, Marina V. Pavlenko Institute of Biology and Soil Science FEB RAS, Vladivostok, 690022, Russia.
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DIFFERENTIATION AND SYSTEMATICS IN THE LONG-TAILED GROUND SQUIRREL, SPERMOPHILUSUNDULATUS (SCIURIDAE, RODENTIA) Marina V. Tsvirka, Vladimir P. Korablev, Marina V. Pavlenko Institute of Biology and Soil Science FEB RAS, Vladivostok, 690022, Russia
Map of the ground squirrels distribution in the Palaearcticregion
PROBLEM • Genus Spermophilus • Subgenus Urocitellus • Species Spermophilus undulatus • Subspecies • S. u. undulatus, • S. u. intercedens, • S. u. menzbieri, • S. u. jacutensis, • S. u.stramineus, • S. u. eversmanni two geographical forms “eastern” “western” (Vorontsov et al., 1980; Frisman, Vorontsov, 1989) (Gromov, Erbaeva, 1995)
Map of S. undulatus distributions western form eastern form hybrid zone ? species or semispecies
Morphometric data(Popkov, 1978) • Morphotypical study(Linetskiy, Linetskaya 1989) • Karyological data(Korablev, 1988)
THE AIM IS to better understand species subdivision in S. undulatus , and ultimately speciation, in Spermophilus.
THE MAIN TASKSARE • To study genetic variability and differentiation of S. undulatus based on nuclear (RAPD) and mitochondrial (D-loop) DNA. • To assess genetic divergence and phylogenetic relationships among subspesies of S. undulatus. • To specify the taxonomic rank of eversmanni (independent species S. eversmanni or subspecies of S. undulatus) based on the data obtained
MATERIALS Map of sampling localities western form eastern form S. relictus, S. dauricus and S. parryi, S. taurensis and S. xanthoprymnus were chosen for comparative analyses, Tamias sibiricus was chosen as outgroup taxon.
METHODS • Mitochondrial DNA analysis • 5’ end of the D-loop(518 bp) • Calculation of genetic distances based on Kimura two-parametric (K2P) estimator. • Reconstructions: NJ, MP, ML and UPGMA with bootstrap estimation of branching robustness in MEGA 4.0 (Tamura et al., 2007) RAPD-PCR analysis • 166 binary characters including the molecular markers • Ten arbitrary decanucleotide primers • Calculation of genetic distances (Nei, 1972) • Reconstructions: NJ and UPGMA with bootstrap estimation of branching robustness in TREECONW 1.3 b (Van de Peer, De Wacher, 1994 )
polymorphic profiles monomorphic profiles
RESULTS Electrophoregrams of S. undulatus obtained using primers OPD-05 and OPE-20 “eastern” form common for all of subspecies eversmanni menzbiery Marker loci are indicated by arrows.
RAPD analysis Genetic variability among S. undulatus subspecies N –total number of loci, Np– number of polymorphic loci, A –allele frequencies, Р – percentage of polymorphicloci (as the proportion of loci polymorphic withineach population tested).
Parameters of genetic differentiation on RAPD analysis n-number of samples, DN - genetic distances (Nei, 1972), p(Ex) - probability (exact test for interpopulation differentiation (Raymond and Rousset, 1995).
NJ and UPGMA treesbased on RAPD data “eastern” form eversmanni UPGMA “eastern” form eversmanni
mt DNA data • 519 nucleotides; • 92 variable sites, 56 parsimony informative; • Mean pairwise transition/transversion ratios was 1.284. Estimates of mean divergence between main lineages of Spermophilus given as geneticdistances
NJ and UPGMA trees based on KP2 distances calculated from mtDNA data
Genetic distances for nuclear (RAPD) and mitochondrial (mtDNA) genomes
CONCLUSIONS • Both nuclear and mitochondrial DNA analyses showed that the subspecies of “eastern” form were close to each other and far from subspecies of “western” form. • 2. Our molecular genetic data showedan important level of genetic divergence between the animals from Altai (S. u. eversmanni) and Far East of Russia (S. u. intercedens, S. u. menzbieri, S. u. jacutensis), similar to those observed between different Spermophilus species (S. relictus, S. dauricus, S. parryi, S. xanthoprymnus, S. taurensis). • 3. The results confirm a distinct taxonomic position of eversmanni. It should be considered as a species taxon within Urocitellus group.
ACKNOWLEDGMENTS • The study was supported by the RFBR (grant nos. 06-04-39015) and FEBRAS (grant nos. 09-III-В-138). THANKS FOR YOUR ATTENTION