Vol 59, No 4 (2023)

Mutations in the NBAS gene cause two groups of diseases – SOPH-syndrome and Infantile liver failure syndrome type 2 (ILFS2, RALF), which differ in clinical manifestations, course, and prognosis. In the current review we focused on clinical and genetic aspects of these pathologies and molecular biology of the NBAS protein, its retrograde membrane traffic and nonsense-mediated RNA decay.

The genetic relatedness of yeasts in the Saccharomyces bayanus complex has been studied using the methods of molecular and classical genetics. A divergent population of S. bayanus has been found in New Zealand and Australia. The S. bayanus complex includes four genetic populations: S. bayanus var. bayanus, S. bayanus var. uvarum, S. eubayanus and New Zealand population. The strains of the New Zealand population differ significantly in the nucleotide sequences of nuclear (FSY1, HIS3, MET2) and mitochondrial (FUN14, COX2) genes and form semi-sterile hybrids with other populations: viability of ascospores is 6.2–23.3%. There is no complete interspecific postzygotic isolation between S. bayanus var. bayanus, S. bayanus var. uvarum, S. eubayanus, and New Zealand populations: all hybrids showed regular meiotic segregation of control auxotrophic markers. According to the results obtained, four genetic populations belong to the same biological species with genomic divergence at the level of taxonomic varieties.

The color of Zea mays L. kernel is determined by the content and composition of carotenoids, including provitamin A, which is a product of the β-β (β-carotene, β-cryptoxanthin) and β-ε (α-carotene) branches of carotenogenesis. The ratio of the fluxes of the branches depends on the activity of the lycopene-ε-cyclase LcyE, which determines the β-ɛ branch. In this work, we analyzed allelic variants of the LcyE gene, which are potentially effective for increasing the biosynthesis of β-carotene, in 20 maize inbred lines of domestic selection, which differ in grain color. The 5'-UTR region of the LcyE gene were amplified and sequenced. Fragment analysis showed the presence of allele “2” in four lines and a new allele “5” in 16 lines. The polymorphism of the new allele “5” was characterized – four mononucleotide polymorphisms and two deletions. The comparison of cis-regulatory elements in the analyzed region of the 5'-UTR of alleles “2” and “5” revealed a difference in binding sites with transcription factors. Expression of the LcyE gene was determined in the leaves of two lines with the allele “2” and three lines with the allele “5”. A direct relationship was shown between the presence of the allele “5” and a decrease in gene expression: the level of gene transcription in the case of the allele “2” was 10–15 times higher than in the case of the allele “5”. It has been suggested that the presence of allele “5” of the LcyE gene in the maize genome correlates with a decrease or suppression of the LcyE expression and, with stable activity of other carotenogenesis enzymes, with grain color. The use of allele “5” donors in combination with the known dark yellow or orange color of the grain can be used in the breeding of maize with increased synthesis of provitamin A in the grain.

For the first time, a karyological and molecular genetic (COI, cytochrome b, 16S rRNA genes) study of the freshwater fish species Cottus kolymensis, recently described from the Dukcha and Kolyma rivers in northeast Asia, was carried out. A complex of karyological and molecular-genetic marker traits has been determined to identify the species. Genetic differences between the populations of C. kolymensis inhabiting the water bodies of the river basins of Kolyma and the northern part of the Sea of Okhotsk were found. On their basis the species is divided into groups in accordance with the habitat. The existence of a separate group “Cottus poecilopus” within the genus Cottus, which includes taxa of the species rank, including C. kolymensis, has been confirmed.

The haplotype diversity of mtDNA of the circumpolar species of ladybirds Adalia frigida collected in Yakutsk and Salekhard was studied. Based on the analysis of the nucleotide sequences of the cox1 gene, 18 mitochondrial haplotypes were identified, of which 14 were new. Of the 18 haplotypes of A. frigida, two (H32 and H9) are the most common. In the Salekhard region, the range of A. frigida overlaps with that of another closely related species, A. bipunctata. The value of divergence in the cox1 gene between A. frigida and A. bipunctata reaches 4.1–4.3% and corresponds to the level of differences characteristic of closely related species. These species are able to interbreed, the share of hybrid individuals (A. frigida and A. bipunctata) in Salekhard is 56.5%. Hybridization between A. frigida and A. bipunctata led to mutual mitochondrial introgression, which resulted in the acquisition of the H1 haplotype by the A. frigida beetles and the H9 haplotype by the A. bipunctata beetles.

The polymorphism of the rs1815739 locus of the ACTN3 gene and the rs11227639 cis-eQTL that affects expression of this gene was studied in the populations of the northern (Chukchi, Koryaks, Evens, and Evenks) and southern (Buryats, Altaians, and Tuvinians) parts of Siberia. It was shown that the frequencies of the rs1815739-C allele of the ACTN3 gene (corresponding to the 577R amino acid variant) and the rs11227639-A upregulating ACTN3 allele, which increases the expression level of this gene, are significantly higher in the north than in the south of Siberia. Similarly, in the northern direction, the frequency of the combination of CC/AA genotypes at these loci increases. The revealed pattern of the geographical distribution of alleles and genotypes at the rs1815739 and rs11227639 loci in Siberian populations may be due to adaptation to cold and the processes of thermoregulation of the body when exposed to cold. It is assumed that an increase in the frequency of rs1815739-C and rs11227639-A alleles in the aboriginal populations of the north of Siberia is associated with an increase in the role of shivering thermogenesis during adaptation to cold exposure, and also contributes to an increase in muscle mass in their carriers, which reduces heat loss in the conditions of the North.

The AS3MT gene encodes arsenic(III) methyltransferase. VNTR polymorphism of the AS3MT gene is characteristic only for the human genome. It is associated with the expression of a human-specific AS3MT^d2d3 protein isoform, which is a potential risk factor for the development of schizophrenia. In this study, we for the first time have analyzed the distribution of frequencies of alleles and genotypes of VNTR polymorphism in a large sample of ethnic Russians. The association of VNTR with the risk of schizophrenia has been studied. The study included 1002 patients with schizophrenia and schizophrenia spectrum disorders and 1510 people of the control group. Women with the V3/V3 genotype have an increased risk of schizophrenia (OR = 1.4, 95% CI: 1.11–1.77).