ISSN 1022-7954, Russian Journal of Genetics, 2006, Vol. 42, No. 6, pp. 595–604. © Pleiades Publishing, Inc., 2006. Original Russian Text © A.A. Bannikova, N.S. Bulatova, D.A. Kramerov, 2006, published in Genetika, 2006, Vol. 42, No. 6, pp. 737–747. 595 INTRODUCTION The common shrew Sorex araneus L., 1758 exhibits a striking range of interspecific karyotype variability, associated with Robertsonian polymorphism [1, 2]. The species proper is represented by a mosaic of distinct chromosome races, differing by the arm composition in metacentric chromosomes [3, 4]. To date, 70 chromo- some races have been described across the vast range of Sorex araneus, extending from northern Europe to the Baikal Lake [5, 6]; of these, 14 races occur in European Russia and 7 races, in Siberia. The common shrew karyotype with a relatively low for mammals diploid number has formed during the evolution of the genus Sorex by centric fusions, which seem to progress also at the intraspecific level [7, 8]. The same number 2n = 20, minimum for the species, is attained by fusion of ten original acrocentrics in various pairwise combinations. The assignment to a chromo- some race is established by the order of pairwise arm combinations in diagnostic metacentrics and free acro- centrics, which are denoted by Latin letters from “g” to “r” in the standard nomenclature of Sorex araneus chromosomes [9]. Chromosome polymorphism of the common shrew, genetic exchange among chromosome races, and the problem of reproductive barriers are currently exten- sively studied by means of such molecular genetic markers as mtDNA, microsatellites, and allozymes. However, mitochondrial markers, which indicate very recent time of formation of most chromosome races, do not allow to differentiate them by haplotypes, whose vast diversity form a starlike phylogeny [4, 10–12]. Allozymes are characterized by low inter- and intrara- cial variation [13]. By contrast, microsatellites are char- acterized by extremely high mutation rates, which results in biased estimates of gene exchange among races [14–16]. In view of the above, the molecular evolution of this species remains rather vague. No reliable molecular markers for chromosome races have been found, the only safe approach to race diagnostics still being kary- otype analysis. This fact is of importance, since it sug- gests possible independence of molecular and chromo- some evolution of the common shrew. It is also noteworthy that investigations of molecular variability, which are carried out along with studies of chromosome polymorphism in the common shrew, Molecular Variability in the Commom Shrew Sorex araneus L. from European Russia and Siberia Inferred from the Length Polymorphism of DNA Regions Flanked by Short Interspersed Elements (Inter-SINE PCR) and the Relationships between the Moscow and Seliger Chromosome Races A. A. Bannikova 1 , N. S. Bulatova 2 , and D. A. Kramerov 3 1 Moscow State University, Moscow, 119992 Russia 2 Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, 119991 Russia 3 Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia; e-mail: hylomys@mail.ru Received November 23, 2005 Abstract—Genetic exchange among chromosomal races of the common shrew Sorex araneus and the problem of reproductive barriers have been extensively studied by means of such molecular markers as mtDNA, micro- satellites, and allozymes. In the present study, the interpopulation and interracial polymorphism in the common shrew was derived, using fingerprints generated by amplified DNA regions flanked by short interspersed repeats (SINEs)—interSINE PCR (IS–PCR). We used primers, complementary to consensus sequences of two short retroposons: mammalian element MIR and the SOR element from the genome of Sorex araneus. Genetic dif- ferentiation among eleven populations of the common shrew from eight chromosome races was estimated. The NJ and MP analyses, as well as multidimensional scaling showed that all samples examined grouped into two main clusters, corresponding to European Russia and Siberia. The bootstrap support of the European Russia cluster in the NJ and MP analyses was respectively 76 and 61%. The bootstrap index for the Siberian cluster was 100% in both analyses; the Tomsk race, included into this cluster, was separated with the bootstrap support of NJ/MP 92/95%. DOI: 10.1134/S1022795406060020 MOLECULAR GENETICS