Vol 9, No 1 (2011)

Chromosome numbers for some species of Central Asia steppe shrubs are given: Rhamnus erythroxylon Pall. (Rhamnaceae), Caragana buriatica Peschk. (Fabaceae), Amygdalus pedunculata Pall., Armeniaca sibirica (L.) Lam. (Rosaceae), Atraphaxis pungens (Bieb.) Jaub. et Spach. and A. frutescens (L.) C. Koch (Polygonaceae). Chromosome numbers of some species were determined for the first time. Comparative analysis of adaptive properties of polyploid and diploid species has been conducted. It was established that natural polyploids are more adaptive to existence in extreme conditions. They possess by high potential for survival and characterized by more high level of intraspecific polymorphism, abundant flowering and fruitification, ability of propagate both generative and vegetative means, high seed germination. 

Polymorphism of the mtDNA gene COI was studied in a St. Petersburg population of two spot ladybird Adalia bipunctata and analyzed in relation with the presence of a symbiotic bacterium Spiroplasma. Variable nucleotide sequences in the middle part of the gene COI formed 13 mitotypes. 84 ladybirds were studied, 21 of these were found to be infected by Spiroplasma. Mean pairwise difference of nucleotides in the COI sequence was 0.001 for uninfected and 0.020 for infected individuals, thus mtDNA polymorphism was considerably higher among uninfected ladybirds compared with infected ones. 

Investigation of Y chromosome haplogroup R1a1a7 (М458) in ethnic Belarusians from six historic and ethnographic regions has shown that its frequency makes up 14% out of total Y chromosome gene pool diversity. Bearers of R1a1a7 (М458) are concentrated in Pripiat and Neman river basins which is in south and west of Belarus respectively. Expansion of R1a1a7 (М458) on the territory of present day Belarus was most probable associated with the distribution of agriculture in Eastern Europe. In addition, obtained data point to presence of later migration wave, Polab Slavs, for example, from Elba and Oder interfluves in Neman river basin at the border of I–II Millennia. 

In nature, microorganisms experience numerous environmental stresses and generally grow poorly most of the time. In the last two decades it has become evident that mutations arise not only in actively dividing cells but also in nonreplicating or slowly replicating cells starved for nutrients. In yeast, precise base selection and proofreading by replicative DNA polymerases δ and ε keep starvation-associated mutagenesis (SAM) at basal levels. Less is known about the role of replicative DNA polymerase α (Pol α). Here we provide evidence that Pol α is involved in the control of SAM in yeast cells starved for adenine by participation in sporadic replication and/or DNA repair under these conditions.