Muskoxen (Ovibos moschatus) are an integral component of Arctic biodiversity. Given low genetic diversity, their ability to respond to future and rapid Arctic change is unknown, although paleontological history demonstrates adaptability within limits. We discuss status and limitations of current monitoring, and summarize circumpolar status and recent variations, delineating all 55 endemic or translocated populations. Acknowledging uncertainties, global abundance is ca 170 000 muskoxen. Not all populations are thriving. Six populations are in decline, and as recently as the turn of the century, one of these was the largest population in the world, equaling ca 41% of today’s total abundance. Climate, diseases, and anthropogenic changes are likely the principal drivers of muskox population change and result in multiple stressors that vary temporally and spatially. Impacts to muskoxen are precipitated by habitat loss/degradation, altered vegetation and species associations, pollution, and harvest. Which elements are relevant for a specific population will vary, as will their cumulative interactions. Our summaries highlight the importance of harmonizing existing data, intensifying long-term monitoring efforts including demographics and health assessments, standardizing and implementing monitoring protocols, and increasing stakeholder engagement/contributions.

In this study, we present the first complete mitochondrial genomes of two species of the genus Ovis – snow sheep (Ovis nivicola) and thinhorn sheep (Ovis dalli). The mitochondrial genomes have a total length of 16,471 and 16,464 bp, respectively, including 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and a non-coding region. Phylogenetic analyses using nucleotide sequences of the 13 PCGs indicated that O. nivicola and O. dalli clustered with another representative of the Pachyceros subgenus – O. canadensis, which was consistent with the previous morphological classification.

Currently, the intraspecific taxonomy of snow sheep (Ovis nivicola) is controversial and needs to be specified using DNA molecular genetic markers. In our previous work using whole-genome single nucleotide polymorphism (SNP) analysis, we found that the population inhabiting Kharaulakh Ridge was genetically different from the other populations of Yakut subspecies to which it was usually referred. Here, our study was aimed at the clarification of taxonomic status of Kharaulakh snow sheep using mitochondrial cytochrome b gene. A total of 87 specimens from five different geographic locations of Yakut snow sheep as well as 20 specimens of other recognized subspecies were included in this study. We identified 19 haplotypes, two of which belonged to the population from Kharaulakh Ridge. Median-joining network and Bayesian tree analyses revealed that Kharaulakh population clustered separately from all the other Yakut snow sheep. The divergence time between Kharaulakh population and Yakut snow sheep was estimated as 0.48 ± 0.19 MYA. Thus, the study of the mtDNA cytb sequences confirmed the results of genome-wide SNP analysis. Taking into account the high degree of divergence of Kharaulakh snow sheep from other groups, identified by both nuclear and mitochondrial DNA markers, we propose to classify the Kharaulakh population as a separate subspecies.

Bovidae, the largest family in Pecora infraorder, are characterized by a striking variability in diploid number of chromosomes between species and among individuals within a species. The bovid X chromosome is also remarkably variable, with several morphological types in the family. Here we built a detailed chromosome map of musk ox (Ovibos moschatus), a relic species originating from Pleistocene megafauna, with dromedary and human probes using chromosome painting. We trace chromosomal rearrangements during Bovidae evolution by comparing species already studied by chromosome painting. The musk ox karyotype differs from the ancestral pecoran karyotype by six fusions, one fission, and three inversions. We discuss changes in pecoran ancestral karyotype in the light of new painting data. Variations in the X chromosome structure of four bovid species nilgai bull (Boselaphus tragocamelus), saola (Pseudoryx nghetinhensis), gaur (Bos gaurus), and Kirk’s Dikdik (Madoqua kirkii) were further analyzed using 26 cattle BAC-clones. We found the duplication on the X in saola. We show main rearrangements leading to the formation of four types of bovid X: Bovinae type with derived cattle subtype formed by centromere reposition and Antilopinae type with Caprini subtype formed by inversion in XSB1.

The paper evaluates the experience of intentional introduction of mammals into Yakutia. The total of eight alien and one native mammal species were introduced during the period between 1930 and 2020. Two alien species (the muskrat and American mink) naturalized successfully, as well as the reintroduced sable. Introduction of the muskox launched in 1996 has proved successful, and with the proper conservation measures, one can expect a further increase in its abundance and expansion of its range to cover the entire tundra zone of Yakutia. Attempts to introduce the Eurasian beaver, raccoon dog, steppe polecat, and domestic yak have failed. Efforts on the introduction of the wood bison continue, but its reproduction rate and specifics of its winter behavior and feeding habits suggest difficulties in the adaptation to new climate conditions. Intentional introduction of alien species poses a potential threat to ecosystems of the North, particularly from attempting to reconstruct paleofauna by introducing the species characteristic of paleolandscapes rather than recent fauna of the region. In the absence of the comprehensive biological analysis, efforts directed at “increasing the biodiversity” can lead to disturbance of the balance of the northern ecosystems.

A comparative study of the allele pool and the genetic structure of two Russian and one Belarusian populations of the wisent Bison bonasus against the repr