Vol 59, No 3 (2023)

The biased expression of parental alleles plays a fundamental role in the formation of the placenta as a multifunctional organ necessary for the development and survival of the fetus. First of all, this is expressed in the phenomenon of imprinting, when only the maternal or paternal allele is expressed in placental cells. The placenta uses an extended range of imprinting mechanisms compared to the embryo – histone modifications that suppress or, conversely, activate the expression of nearby genes, regulatory sequences and genes derived from retroviruses or retrotransposons, microRNAs that function as antisense RNAs and participate in transcriptional and post-transcriptional regulation of gene expression. In addition, incomplete suppression of the activity of one of the parental alleles is detected in the placenta, leading to a biased imprinted expression of some genes. This review shows the role of biased expression of parental alleles in the development of placental structures of an embryo, discusses the mechanisms of epigenetic control of parental alleles, mainly expressed in the placenta.

The ATOX1 (Antioxidant Protein 1) is a human copper metal chaperone that plays an important role in cellular copper homeostasis. The protein is responsible for cytosolic copper absorption from CTR1 (copper transporter 1) and transport to the copper pumps in the Trans Golgi network to the ATP7A and ATP7B proteins. This review collected data on the antioxidant role of ATOX1, the gene role in the angiogenesis regulation and cancer cell proliferation, and the role in the copper-induced diseases pathogenesis – Wilson’s disease and Menkes disease.

Polycomb and Trithorax group proteins (PcG and TrxG) are epigenetic factors responsible for the repression and activation of transcription, respectively. In Drosophila, PcG/TrxG proteins are recruited to specialized DNA elements called PRE (Polycomb response elements). Depending on the context, these elements may repress, activate, or be neutral with respect to the promoter of the target gene. Previously, in transgenic studies using PhiC31 site-specific integration system, we have demonstrated that sites for architectural proteins inserted next to PRE can induce the repressive activity of bxdPRE by stimulating the binding of PcG/TrxG factors to this element. However, this effect may depend on additional DNA elements present at the integration site after PhiC31-dependent transgene insertion. In the present study, using an alternative system of integration based on CRISPR/Cas9-catalyzed homology-directed repair, we have proved that the binding sites of the architectural protein Su(Hw) are indeed able to induce the repressive activity of bxdPRE and recruitment of PcG/TrxG proteins, regardless the heterogenous DNA-sequences present at the site of integration after PhiC31-dependent insertion of the transgenes.

The structure of genetic variation of the common juniper (Juniperus communis L.), a widespread wind-pollinated golarctic shrub of Cupressaceae was surveyed. We used 7 microsatellite markers including three new to genotype samples from 23 Eurasian populations and one from North America (Alaska). The geographical patterns are interpreted jointly with our previously available chloroplast DNA data. High genetic diversity was revealed with highest values in the same northern populations (Sweden, Estonia, Mezen, Polar Urals, Yamal, Kolyma, as well as in the Alps) as previously identified at cpDNA analysis. Nuclear markers exhibited a lower level interpopulation differentiation (F_ST = 9.8%) than chloroplast markers (F_ST = 76%). Bayesian cluster analysis showed that the optimal number of genetic groups (K) was two. All the 24 populations of J. communis were divided into the East group (north-east and Far East of Russia, Alaska and Himalayan) and the West group (Europe, Ural and Siberia). In the Alpine and Mountain Shoria populations, genotypes from different genetic groups are combined.

As a result of the study, we confirmed the high differentiating potential of polymorphic variants g.27748425T>C (ADCY8 gene) and g.1414373T>C (RYR3 gene). A test model of two polymorphisms for the differentiation of a wolf and a domestic dog is proposed, which is distinguished by high values of accuracy (96.2%), specificity (96.3%) and sensitivity (98.9%). Using KASP, a quick and simple approach to differentiation based on the proposed test model has been developed, which is designed to reduce the time and cost of molecular genetic analysis, as well as reduce the risk of cross-contamination, because the process is one-stage (restriction and electrophoresis stages are excluded).

Variability of 27 autosomal STR loci of the ForenSeq DNA Signature Prep Kit (Illumina) commercial panel was studied using the technology of mass parallel sequencing (MPS) in 733 unrelated individuals representing the population of the Republic of Belarus as well as a population base of MPS allele frequencies for expert probabilistic calculations in human identification and paternity establishment was evaluated. The agreement between genotypes obtained by MPS and capillary electrophoresis (CE) was 99.96%. The number of MPS alleles increased more than two times for eight loci (D12S391, D21S11, D2S1338, vWA, D3S1358, D8S1179, D13S317, D9S1122). Thirteen alleles detected were not included in the STRSeq BioProject catalog of the international online database STRbase 2.0. The random match probability of 27-locus MPS profiles decreased from 1.43 × 10^–31 to 2.89 × 10^–35, and the combined paternity index increased from 2.08 × 10¹⁰ to 3.25 × 10¹² compared to CE data.