Vol 7, No 4 (2009)

Precise DNA-DNA reassociation data were obtained for new biological species S. cariocanus, S. kudriavzevii and S. mikatae, for the first time. The three species showed 25-51 % - of DNA-DNA reassociation with one another and with the known species S. cerevisiae, S. bayanus and S. paradoxus.Only in the combination S. paradoxus × S. cariocanus there was 99 % DNA-DNA homology. Despite high DNA-DNA reassociation value, the two yeasts are genetically isolated: their hybrids are sterile forming non-viable meiotic products (ascospores). Having four reciprocal translocations in its karyotype, S. cariocanus represents species in statu nascendi.

The article describes differences in a response of linseed cultivars of a different genetic and geographical origin to a set of ecological factors. Variability in productivity traits was revealed to be determined in most cases by a genotype and its interaction with growing conditions. The genotype and environmental conditions exert an equal effect on oil accumulation in seeds and its qualitative composition. Based on the data obtained from the linseed collection, the most ecologically stable genotypes, displaying steadily high seed productivity in combination with high content and quality of oil, were selected.

Composition of Adalia bipunctata population "University" (collected near St. Petersburg University) was studied from 1975 till 2009, also considering the data obtained by J. Lusis who sampled this ladybird population in 1933, 1934, and 1947. The part of black-colored forms in the population decreased from 90.0 % in 1933 to 47.8 % in 2009. Two hypotheses explaining the observed population dynamics are suggested and discussed: ecological (effect of the city air pollution) and genetic (replacement of the black-color allele with more efficient polygenic system).

The association of 13 biallelic polymorphisms of genes hOGG1 977C > G, XPD1 2251A > C, XPG1 3310G > C, XRCC1:580C> T, 839G >A, 1196G>A GSTT1 («+»/«-»), GSTM1 («+»/«-»), CYP2C19 681G> A, NOS3: -665C>T, 774С> T, 894G > T, VNTRint4 with risk of development of malignant new growths (MNG) in conditions of "low-dose" ionizing irradiation was investigated. In 1 group of irradiated patients of malignant new growths there are 96 persons, in 2 group of non-irradiated patients of MNG - 135 persons, in 3 control group - 148 healthy irradiated workers of the Siberian Group of Chemical Enterprises. By means of procedure FDR it is shown that only polymorphic variants of gene CYP2C19681G* are authentically associated with risk of occurrence of MNG against an irradiation. 1 genotype consisting of a combination of 5 polymorphic loci is selected. Frequency of occurrence of this genotype in 1 group makes 16,9 % (14/83), in 2 group - 1,0 % (1/100), in 3 group - 0,84 % (1/119). At its carriers in conditions of low-dose irradiation more than in 20 times the risk of occurrence of MNG (OR between 1 and 3 groups (95 % CI) = 24,14 (3,21-502,64) increases; p = 0,0000581, taking into account the correction of Bonferroni р = 0,01046).

In a system of Drosophila P-element activation at 25 °С and 18 °С we observed the increase of the gene conversion frequency among the offspring of parents containing nonautonomous P-elements and a chromosome with rad201^G1 mutation in genome. The similar increase of conversion events in this system was shown in the experiments with mutation mei41D5. In both cases inheritance of the increased gene conversion frequency had an epigenetic character, since increased conversion was observed also among the offspring not carrying mutations rad201^G1 or mei41D5.