In different countries, interest in the commercial cultivation of the olive has recently greatly increased, which has led to the expansion of its range. The Crimean Peninsula is the northern limit of the common olive (Olea europaea L.) range. A unique collection of common olive’s cultivars and hybrids has been collected in the Nikitsky Botanical Gardens (NBG). The aim of this study was to assess the genetic diversity of 151 samples (total of several biological replicates of 46 olive cultivars including 29 introduced and 11 indigenous genotypes) using the ddRAD sequencing method. Structural analysis showed that the studied samples are divided into ten groups, each of which mainly includes cultivars of the same origin. Cultivars introduced to the Crimean Peninsula from different regions formed separate groups, while local cultivars joined different groups depending on their origin. Cultivars of Crimean origin contain admixtures of mainly Italian and Caucasian cultivars’ genotypes. Our study showed that the significant number of Crimean cultivars contains an admixture of the Italian cultivar “Coreggiolo”. Genetic analysis confirmed the synonymy for the cv. “Otur” and “Nikitskaya 2”, but not for the other four putative synonyms. Our results revealed the genetic diversity of the olive collection of NBG and provided references for future research studies, especially in selection studies for breeding programs.

About ten species of the genus Actinidia Lindl. are known as cultivated plants—alongside the most known A. chinensis var. deliciosa, there are many others, including Far-Eastern cold-hardy kiwifruits such as A. arguta, A. kolomikta, and A. polygama. Unlike most plant species, in which the chloroplast genome is maternally inherited, the family Actinidiaceae possesses a complex system of plastid inheritance with possible transmission through both maternal and paternal lines. The main aim of this work was the assembly of the plastid genomes of three species of Actinidia, their comparison with already-available sequences from databases, and evolutionary analyses. We discovered that the gene composition and gene sequences are conserved; the studied species are either subject to purifying selection or not subject to selection at all (with some exceptions, such as the ycf2 gene). However, the chloroplast chromosomes of some Actinidia species have undergone significant structural rearrangements, leading to the persistence of two main forms, both on an intrageneric and intraspecific level. These results expand our understanding of plastid genomics and genetic diversity within the genus Actinidia, providing a basis for future research in molecular marker development, phylogenetic analysis, and population studies.

Paleoclimatic changes during the Pleistocene–Holocene transition is suggested as a main factor that led to species extinction, including the woolly mammoth (Mammuthus primigenius), Steller’s sea cow (Hydrodamalis gigas) and the Don-hare (Lepus tanaiticus). These species inhabited the territory of Eurasia during the Holocene, but eventually went extinct. The Don-hare is an extinct species of the genus Lepus (Leporidae, Lagomorpha), which lived in the Late Pleistocene–Early Holocene in Eastern Europe and Northern Asia. For a long time, the Don-hare was considered a separate species, but at the same time, its species status was disputed, taking into account both morphological data and mitochondrial DNA. In this study, mitochondrial genomes of five Don-hares, whose remains were found on the territory of Northeastern Eurasia were reconstructed. Firstly, we confirm the phylogenetic proximity of the “young” specimens of Don-hare and mountain or white hare, and secondly, that samples older than 39 Kya form a completely distinct mitochondrial clade.

Significant palaeoecological and paleoclimatic changes that took place during Late Pleistocene—Early Holocene transition are considered important factors that led to megafauna extinctions. Unlike many other species, the brown bear (Ursus arctos) has survived this geological time. Despite the fact that several mitochondrial DNA clades of brown bears became extinct at the end of the Pleistocene, this species is still widely distributed in Northeast Eurasia. Here, using the ancient DNA analysis of a brown bear individual that inhabited Northeast Asia in the Middle Holocene (3460 ± 40 years BP) and comparative phylogenetic analysis, we show a significant mitochondrial DNA similarity of the studied specimen with modern brown bears inhabiting Yakutia and Chukotka. In this study, we clearly demonstrate the maternal philopatry of the Northeastern Eurasian U. arctos population during the several thousand years of the Holocene.

Understanding the transcriptional responses of plants under cold stress conditions is critical for olive cultivation, particularly in regions prone to extreme weather fluctuations and especially with increasing threats from climate change. In controlled experiments, we subjected leaves of three cold-tolerant and three cold-susceptible cultivars to moderate (−7 °C) and severe (−12 °C) freezing stress, followed by recovery at baseline temperatures. The study measured photosynthetic efficiency and enzymatic activity and showed physiological and gene expression changes using different methods. Distinct transcriptomic adaptations were revealed. Cultivars displayed enhanced differential expression associated with photosynthetic recovery and gene regulation in metabolic pathways. Two overlapping DEGs with increased expression were found in all cultivars during initial freezing.

The formation and maturation of stone fruits are complex processes that require the involvement of many genes and gene products. Early research on the peach fruit (Prunus persica (L.) Batsch) and the differences in ripening periods of its cultivars mainly focused on the already ripe fruit. However, in the early stages of fruit formation, there may be significant differences between cultivars that have different ripening periods. We identify and analyze differentially expressed genes (DEGs) between flowers, fertilized ovaries, and fruits at the S1 stage in cultivars that have different ripening periods, both between cultivars and from stage to stage. Gene expression in peach cultivars that have different ripening periods differs even in the early stages of fruit formation. The most significantly enriched categories of DEGs in this case are photosynthesis, redox reactions, and processes associated with cell-wall modification; thus, by the time the fruit forms, hormonal reception becomes more important.