Low Levels Of Genetic Diversity Research Articles

The genome of the Pyrenean desman and the effects of bottlenecks and inbreeding on the genomic landscape of an endangered species.

The Pyrenean desman (Galemys pyrenaicus) is a small semiaquatic mammal endemic to the Iberian Peninsula. Despite its limited range, this species presents a strong genetic structure due to past isolation in glacial refugia and subsequent bottlenecks. Additionally, some populations are highly fragmented today as a consequence of river barriers, causing substantial levels of inbreeding. These features make the Pyrenean desman a unique model in which to study the genomic footprints of differentiation, bottlenecks and extreme isolation in an endangered species. To understand these processes, the complete genome of the Pyrenean desman was sequenced and assembled using a Bloom filter‐based approach. An analysis of the 1.83 Gb reference genome and the sequencing of five additional individuals from different evolutionary units allowed us to detect its main genomic characteristics. The population differentiation of the species was reflected in highly distinctive demographic trajectories. In addition, a severe population bottleneck during the postglacial recolonization of the eastern Pyrenees created one of the lowest genomic heterozygosity values recorded in a mammal. Moreover, isolation and inbreeding gave rise to a high proportion of runs of homozygosity (ROH). Despite these extremely low levels of genetic diversity, two key multigene families from an eco‐evolutionary perspective, the major histocompatibility complex and olfactory receptor genes, showed heterozygosity excess in the majority of individuals, revealing that functional diversity can be maintained up to a certain extent. Furthermore, these two classes of genes were significantly less abundant than expected within ROH. In conclusion, the genomic landscape of each analysed Pyrenean desman turned out to be strikingly distinctive and was a clear reflection of its recent ancestry and current conservation conditions. These results may help characterize the genomic health of each individual, and can be crucial for the conservation and management of the species.

A population genetics study of three native Mexican woody bamboo species of Guadua (Poaceae: Bambusoideae: Bambuseae: Guaduinae) using nuclear microsatellite markers

Background: Sporadic flowering contributes significantly to genetic diversity and connectivity among populations. Woody bamboos present sporadic or gregarious flowering patterns with long flowering cycles. In this study, we analyze the genetic diversity of three Guadua species distributed along the Gulf of Mexico slope that have different patterns of flowering. 
 Questions: (1) Are the three Guadua species genetically differentiated? (2) Does the vulnerable species G. inermis have low levels of genetic diversity? (3) What is the relative contribution of geographic and environmental factors to the genetic structure of G. inermis ?
 Species studied: Guadua inermis , G. amplexifolia and G. tuxtlensis 
 Study site and dates: During 2014 and 2015, we collected samples of G. inermis in Puebla and southeastern Mexico, G. amplexifolia in Veracruz and Oaxaca, and G. tuxtlensis in southern Veracruz.
 Methods: We successfully amplified five of nine SSR markers, and genotyped a total of 155 samples.
 Results: The three Guadua species were genetically differentiated. For G. inermis , we found high levels of population genetic diversity, which are relatively higher than those of other monocot species. Genetic differentiation was high and three groups were detected: north, central and south. We found a significant association between genetic distances and the maximum temperature of the warmest month, but not with geographic distance. 
 Conclusions: Our study is the first to analyze levels of genetic diversity in Mexican bamboos and confirms their taxonomic identity. G. inermis has a strong genetic structure, even when populations are geographically close.

High genetic diversity and low differentiation of endangered Ferula tadshikorum Pimenov in Tajikistan

Comprehensive research on the genetic diversity and structure of small populations of endangered plants is a prerequisite for their effective conservation and management. Ferula tadshikorum is a critically endangered herbaceous medicinal plant, which has a declining population size in southern Tajikistan. Lack of information about the genetic diversity is a major obstacle in formulating appropriate management strategies for its protection. The present study analysed the genetic diversity and structure of 196 individual plants from six populations by studying a total of 123 alleles. High level of genetic diversity (hS = 0.613, hT = 0.626,Ho=0.728,He= 0.605,PIC= 1.207, PPB= 100%) and low levels of genetic variation and differentiation (Fst = 0.029) among populations were detected. It should be noted that no recent genetic bottleneck was observed in the six populations. Structural analysis divided all individuals into two genetic clusters but failed to categorise the populations. Given the association between overexploitation and a decline in the population size of Ferula species, several strategies, including establishing in situ conservation, artificial breeding in botanical gardens for ex situ conservation, developing large-scale artificial cultivation, and exploring synthetic pathways of active components from wild resources, have also been proposed.

Whole genome sequencing reveals high differentiation, low levels of genetic diversity and short runs of homozygosity among Swedish wels catfish

The use of genetic markers in the context of conservation is largely being outcompeted by whole-genome data. Comparative studies between the two are sparse, and the knowledge about potential effects of this methodology shift is limited. Here, we used whole-genome sequencing data to assess the genetic status of peripheral populations of the wels catfish (Silurus glanis), and discuss the results in light of a recent microsatellite study of the same populations. The Swedish populations of the wels catfish have suffered from severe declines during the last centuries and persists in only a few isolated water systems. Fragmented populations generally are at greater risk of extinction, for example due to loss of genetic diversity, and may thus require conservation actions. We sequenced individuals from the three remaining native populations (Båven, Emån, and Möckeln) and one reintroduced population of admixed origin (Helge å), and found that genetic diversity was highest in Emån but low overall, with strong differentiation among the populations. No signature of recent inbreeding was found, but a considerable number of short runs of homozygosity were present in all populations, likely linked to historically small population sizes and bottleneck events. Genetic substructure within any of the native populations was at best weak. Individuals from the admixed population Helge å shared most genetic ancestry with the Båven population (72%). Our results are largely in agreement with the microsatellite study, and stresses the need to protect these isolated populations at the northern edge of the distribution of the species.

The Nero Lucano Pig Breed: Recovery and Variability.

Simple SummaryThe reduction of biodiversity determines the loss of species and breeds, with the consequent disappearance of production systems, knowledge, cultures and local traditions. The Nero Lucano pig is a native breed of Southern Italy (Basilicata region) recovered, starting from 2001, because of the high quality of its cured meat products. This study gives a picture of the low genetic variability of this breed. Knowledge of individual inbreeding levels allows for planning of interventions to reduce the negative effects of the low effective population size and, then, improve the efficiency of the actual recovery project.The Nero Lucano (NL) pig is a black coat colored breed characterized by a remarkable ability to adapt to the difficult territory and climatic conditions of Basilicata region in Southern Italy. In the second half of the twentieth century, technological innovation, agricultural evolution, new breeding methods and the demand for increasingly lean meat brought the breed almost to extinction. Only in 2001, thanks to local institutions such as: the Basilicata Region, the University of Basilicata, the Regional Breeders Association and the Medio Basento mountain community, the NL pig returned to populate the area with the consequent possibility to appreciate again its specific cured meat products. We analyzed the pedigrees recorded by the breeders and the Illumina Porcine SNP60 BeadChip genotypes in order to obtain the genetic structure of the NL pig. Results evidenced that this population is characterized by long mean generation intervals (up to 3.5 yr), low effective population size (down to 7.2) and high mean inbreeding coefficients (FMOL = 0.53, FROH = 0.39). This picture highlights the low level of genetic variability and the critical issues to be faced for the complete recovery of this population.

Vulture Genomes Reveal Molecular Adaptations Underlying Obligate Scavenging and Low Levels of Genetic Diversity.

Obligate scavenging on the dead and decaying animal matter is a rare dietary specialization that in extant vertebrates is restricted to vultures. These birds perform essential ecological services, yet many vulture species have undergone recent steep population declines and are now endangered. To test for molecular adaptations underlying obligate scavenging in vultures, and to assess whether genomic features might have contributed to their population declines, we generated high-quality genomes of the Himalayan and bearded vultures, representing both independent origins of scavenging within the Accipitridae, alongside a sister taxon, the upland buzzard. By comparing our data to published sequences from other birds, we show that the evolution of obligate scavenging in vultures has been accompanied by widespread positive selection acting on genes underlying gastric acid production, and immunity. Moreover, we find evidence of parallel molecular evolution, with amino acid replacements shared among divergent lineages of these scavengers. Our genome-wide screens also reveal that both the Himalayan and bearded vultures exhibit low levels of genetic diversity, equating to around a half of the mean genetic diversity of other bird genomes examined. However, demographic reconstructions indicate that population declines began at around the Last Glacial Maximum, predating the well-documented dramatic declines of the past three decades. Taken together, our genomic analyses imply that vultures harbor unique adaptations for processing carrion, but that modern populations are genetically depauperate and thus especially vulnerable to further genetic erosion through anthropogenic activities.

Population genetic structure of hard clam (Meretrix lyrata) along the Southern coast of Thailand

Abstract. Suppapan J, Sangthong P, Songrak A, Supmee V. 2021. Population genetic structure of hard clam (Meretrix lyrata) along the Southern coast of Thailand. Biodiversitas 22: 2489-2496. The hard clam (Meretrix lyrata), which is an economically important fishery item in Southern Thailand, has decreased rapidly due to overexploitation. To construct sustainable management of this species, genetic information is necessary. In our study, the genetic diversity of M. lyrata was investigated based on the variation of the nucleotide sequence (439 bp) of mitochondrial DNA (mtDNA) in the cytochrome oxidase subunit I gene (mtDNA COI). The mtDNA COI sequences of 145 individuals collecting from 6 sampling sites along the Southern coast of Thailand were analyzed. The results revealed that M. lyrata populations showed moderate to low levels of genetic diversity. All of the population genetic structure analysis revealed the genetic differentiation of the hard clam between the Gulf of Thailand and the Andaman Sea populations. Based on these results, a genetic structure of the hard clam M. lyrata in Southern Thailand was possibly caused by a disruptive gene flow from the geographic factors by the Thai-Malay Peninsula. The demographic history test revealed that the hard clam living in Southern Thailand had experienced population expansion. This study provided the first genetic information that could be used for conserving the hard clam M. lyrata in Southern Thailand.

Genetic Diversity in Diospyros Germplasm in the Western Caucasus Based on SSR and ISSR Polymorphism.

Simple SummaryPersimmon is an edible fruit consisting of several species in the genus Diospyros. The most widely cultivated and most commercially important species is the Oriental persimmon, Diospyros kaki. However, the inter- and intra-specific genetic diversity of the genus Diospyros remains largely unclear and is of great interest both for conservation and breeding purposes. This study describes the genetic diversity and genetic admixture of Diospyros germplasm in the Western Caucasus. The information can be used to support conservation measures and the breeding of persimmon.Persimmon germplasm in the Western Caucasus represent one of the most northerly collections. In our study, 51 commercial cultivars of D. kaki, 3 accessions of D. virginiana and 57 D. lotus accessions from six geographically distant populations were investigated using 19 microsatellite and 10 inter simple sequence repeat (ISSR) markers. After STRUCTURE analysis, the single accessions of Diospyros were allocated to three genetic clusters. Genetic admixtures in the important genotypes of D. kaki were revealed, whereas D. lotus accessions showed no admixture with other genetic clusters. The correspondence of genetic data and phenotypical traits was estimated in the D. kaki collection. The most frost tolerant genotypes of the collection, such as “Mountain Rogers”, “Nikitskaya Bordovaya”, “Rossiyanka”, “MVG Omarova”, “Meader”, “Costata”, “BBG”, and “Jiro”, showed a high percentage of genetic admixtures and were grouped close to D. virginiana. Some of these genotypes are known to be interspecific hybrids with D. virginiana. A low level of genetic diversity between the distant D. lotus populations was revealed and it can be speculated that D. lotus was introduced to the Western Caucasus from a single germplasm source. These results are an important basis for the implementation of conservation measures, developing breeding strategies, and improving breeding efficiency.

Conservation insights from wild bee genetic studies: Geographic differences, susceptibility to inbreeding, and signs of local adaptation.

Conserving bees are critical both ecologically and economically. Genetic tools are valuable for monitoring these vital pollinators since tracking these small, fast‐flying insects by traditional means is difficult. By surveying the current state of the literature, this review discusses how recent advances in landscape genetic and genomic research are elucidating how wild bees respond to anthropogenic threats. Current literature suggests that there may be geographic differences in the vulnerability of bee species to landscape changes. Populations of temperate bee species are becoming more isolated and more genetically depauperate as their landscape becomes more fragmented, but tropical bee species appear unaffected. These differences may be an artifact of historical differences in land‐use, or it suggests that different management plans are needed for temperate and tropical bee species. Encouragingly, genetic studies on invasive bee species indicate that low levels of genetic diversity may not lead to rapid extinction in bees as once predicted. Additionally, next‐generation sequencing has given researchers the power to identify potential genes under selection, which are likely critical to species’ survival in their rapidly changing environment. While genetic studies provide insights into wild bee biology, more studies focusing on a greater phylogenetic and life‐history breadth of species are needed. Therefore, caution should be taken when making broad conservation decisions based on the currently few species examined.

Genetic diversity and population structure of orchid bees from the Brazilian savanna

Based on microsatellite markers and non-lethal sampling of orchid bee males, we assessed the genetic diversity and population structure of three species, Euglossa pleosticta, Euglossa imperialis, and Eulaema nigrita, collected from forest remnants in the Brazilian savanna biome. Among these species, El. nigrita has being acknowledged as more tolerant to savanic areas, since it is more frequently found in these habitats than the other two species. Thus, we hypothesized that species more associated with forest areas would show lower levels of genetic diversity and higher levels of population structure, since open areas could represent a barrier to the movement of these species. We observed lower levels of genetic diversity (HE ) in the species highly associated with forest areas (Eg. pleosticta, HE = 0.66; Eg. imperialis, HE = 0.44) compared to El. nigrita (HE = 0.81). Concerning the genetic structure, it was only remarkable among samples of Eg. pleosticta, a species strongly associated with the forest remnants. Despite the documented dispersal capacity of euglossine bees, maintenance of the connections among forest areas in this biome seems to be critical for their conservation in the Brazilian savanna.

Effects of dispersal strategy and migration history on genetic diversity and population structure of Antarctic lichens

AbstractAimThe homogenisation of historically isolated gene pools has been recognised as one of the most serious conservation problems in the Antarctic. Lichens are the dominant components of terrestrial biotas in the Antarctic and in high mountain ranges of southern South America. We study the effects of dispersal strategy and migration history on their genetic structure to better understand the importance of these processes and their interplay in shaping population structure as well as their relevance for conservation.LocationMaritime Antarctic and southern South America.MethodsPopulations of three fruticose lichen species, Usnea aurantiacoatra, U. antarctica and Cetraria aculeata, were collected in different localities in the Maritime Antarctic and southern South America. Usnea aurantiacoatra reproduces sexually by ascospores, whereas the other two species mostly disperse asexually by symbiotic diaspores. Samples were genotyped at 8–22 microsatellite loci. Different diversity and variance metrics, Bayesian cluster analyses and Discriminant Analysis of Principal Components (DAPC) were used to study population genetic structure. Historical migration patterns between southern South America and the Antarctic were investigated for U. aurantiacoatra and C. aculeata by approximate Bayesian computation (ABC).ResultsThe two vegetative species display lower levels of genetic diversity than U. aurantiacoatra. Antarctic populations of C. aculeata and South American populations of U. aurantiacoatra display much stronger genetic differentiation than their respective counterparts on the opposite side of the Drake Passage. Usnea antarctica was not found in South America but shows comparably low levels of genetic differentiation in Antarctica as those revealed for U. aurantiacoatra. Phylogeographic histories of lichens in the region differ strongly with recent colonisation in some instances and potential in situ persistence during Last Glacial Maximum (LGM) in others. Patterns of genetic diversity indicate the presence of glacial refugia near Navarino Island (South America) and in the South Shetland Islands. ABC analyses suggest that C. aculeata colonised the Antarctic from Patagonia after the LGM. Results for U. aurantiacoatra are ambiguous, indicating a more complex population history than expressed in the simplified scenarios.Main ConclusionsMode of propagation affects levels of genetic diversity, but the location of glacial refugia and postglacial colonisation better explains the diversity patterns displayed by each species. We found evidence for glacial in situ survival of U. aurantiacoatra on both sides of the Drake Passage and postglacial colonisation of Antarctica from South America by C. aculeata. Maintaining the strong genetic differentiation of Antarctic populations of C. aculeata requires strict conservation measures, whereas populations of U. aurantiacoatra are exposed to a much lower risk due to their higher diversity and connectivity.

Insights into the Mitochondrial and Nuclear Genome Diversity of Two High Yielding Strains of Laying Hens.

Simple SummaryMitochondria are commonly known as “the powerhouse of the cell”, influencing the fitness, lifespan and metabolism of eukaryotic organisms. In our study we examined mitochondrial and nuclear genomic diversity in two high yielding strains of laying hens. We tested if the mitochondrial genome affects functional traits such as body weight and phosphorus utilization. We discovered a surprisingly low mitochondrial genetic diversity and an unequal distribution of the haplotypes among both strains, leading to limitations of robust links to phenotypic traits. In contrast, we found similar levels of nuclear genome diversity in both strains. Our study explores the potential influence of the mitochondrial genome on phenotypic traits and thus contributes to a better understanding of the function of this organelle in laying hens. Further, we focus on its usefulness as a genetic marker, which is often underestimated in breeding approaches, given the different inheritance mechanism compared to the nuclear genome.Mitochondria are essential components of eukaryotes as they are involved in several organismic key processes such as energy production, apoptosis and cell growth. Despite their importance for the metabolism and physiology of all eukaryotic organisms, the impact of mitochondrial haplotype variation has only been studied for very few species. In this study we sequenced the mitochondrial genome of 180 individuals from two different strains of laying hens. The resulting haplotypes were combined with performance data such as body weight, feed intake and phosphorus utilization to assess their influence on the hens in five different life stages. After detecting a surprisingly low level of genetic diversity, we investigated the nuclear genetic background to estimate whether the low mitochondrial diversity is representative for the whole genetic background of the strains. Our results highlight the need for more in-depth investigation of the genetic compositions and mito-nuclear interaction in individuals to elucidate the basis of phenotypic performance differences. In addition, we raise the question of how the lack of mitochondrial variation developed, since the mitochondrial genome represents genetic information usually not considered in breeding approaches.

Microsatellite analysis reveals low genetic diversity in managed populations of the critically endangered gharial (Gavialis gangeticus) in India

The gharial (Gavialis gangeticus) is a critically endangered crocodylian, endemic to the Indian subcontinent. The species has experienced severe population decline during the twentieth century owing to habitat loss, poaching, and mortalities in passive fishing. Its extant populations have largely recovered through translocation programmes initiated in 1975. Understanding the genetic status of these populations is crucial for evaluating the effectiveness of the ongoing conservation efforts. This study assessed the genetic diversity, population structure, and evidence of genetic bottlenecks of the two managed populations inhabiting the Chambal and Girwa Rivers, which hold nearly 80% of the global gharial populations. We used seven polymorphic nuclear microsatellite loci and a 520 bp partial fragment of the mitochondrial control region (CR). The overall mean allelic richness (Ar) was 2.80 ± 0.40, and the observed (Ho) and expected (He) heterozygosities were 0.40 ± 0.05 and 0.39 ± 0.05, respectively. We observed low levels of genetic differentiation between populations (FST = 0.039, P < 0.05; G’ST = 0.058, P < 0.05 Jost’s D = 0.016, P < 0.05). The bottleneck analysis using the M ratio (Chambal = 0.31 ± 0.06; Girwa = 0.41 ± 0.12) suggested the presence of a genetic bottleneck in both populations. The mitochondrial CR also showed a low level of variation, with two haplotypes observed in the Girwa population. This study highlights the low level of genetic diversity in the two largest managed gharial populations in the wild. Hence, it is recommended to assess the genetic status of extant wild and captive gharial populations for planning future translocation programmes to ensure long-term survival in the wild.

Ecological and evolutionary drivers of geographic variation in songs of a Neotropical suboscine bird: The Drab-breasted Bamboo Tyrant (Hemitriccus diops, Rhynchocyclidae)

Abstract Understanding the evolutionary and ecological mechanisms that shape the spatial divergence of signals involved in reproductive isolation is a central goal in studies of speciation. For birds with innate songs, such as the suboscine passerine birds, the integration and comparison of both genetic and ecological factors in explaining song variation at the microevolutionary scale are rare. Here, we evaluated the evolutionary and ecological processes underlying the variation in the songs of the Atlantic Forest endemic Drab-breasted Bamboo Tyrant (Hemitriccus diops), testing the effects of both stochastic and adaptive processes, namely the stochastic and acoustic adaptation hypotheses, respectively. We combined vocal, genetic, and ecological (climate and forest cover) data across the species’ range. To this end, we analyzed 89 samples of long and short songs. We performed analyses on raw and synthetic data song variables with linear mixed models and multivariate statistics. Our results show that both song types differ in spectral features between the 2 extant phylogeographic lineages of this species, but such vocal divergence is weak and subtle in both song types. Overall, there is a positive relationship of acoustic distances with the amount of forest cover in long songs. Our results suggest that there is cryptic geographical variation in both song types and that this variation is associated with low levels of genetic divergence in both songs and with ecological factors in long songs.

The mango seed weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae) is characterized by low genetic diversity and lack of genetic structure

The mango seed weevil Sternochetus mangiferae (Fabricius) is distributed across the major mango‐producing areas of the world and causes significant economic losses of mango fruit. Despite its importance as a crop pest, we have only limited information on the population genetics of the mango seed weevil. Here, we examined the genetic diversity of this important pest using specimens intercepted by Beijing Customs District P. R. in China from 41 countries and regions. We used segments of the mitochondrial gene cytochrome c oxidase subunit I and the nuclear gene elongation factor 1‐alpha to examine population genetic structure in this species. Our results showed that genetic diversity is low in S. mangiferae, with a mean genetic distance of 0.095–0.14%. Other population genetic parameters also indicated a low level of genetic diversity among samples from a large geographic range. Analysis of molecular variance revealed little population genetic structure, and mismatch distribution analyses provided evidence of a population expansion, although other demographic metrics of population expansion were nonsignificant. We suggest that the observed low level of genetic diversity and population genetic structure in S. mangiferae supports the hypothesis that the population genetics of this species has been impacted by anthropogenic transportation of mangoes and weevils.

Ocean Currents Drove Genetic Structure of Seven Dominant Mangrove Species Along the Coastlines of Southern China.

Mangrove forest ecosystems, which provide important ecological services for marine environments and human activities, are being destroyed worldwide at an alarming rate. The objective of our study was to use molecular data and analytical techniques to separate the effects of historical and contemporary processes on the distribution of mangroves and patterns of population genetic differentiation. Seven mangrove species (Acanthus ilicifolius, Aegiceras corniculatum, Avicennia marina, Bruguiera gymnorrhiza, Kandelia obovata, Lumnitzera racemosa, and Rhizophora stylosa), which are predominant along the coastlines of South China, were genotyped at nuclear (nSSR) and chloroplast (cpSSR) microsatellite markers. We estimated historical and contemporary gene flow, the genetic diversity and population structure of seven mangrove species in China. All of these seven species exhibited few haplotypes, low levels of genetic diversity (HE = 0.160–0.361, with the exception of K. obovata) and high levels of inbreeding (FIS = 0.104–0.637), which may be due to their marginal geographical distribution, human-driven and natural stressors on habitat loss and fragmentation. The distribution patterns of haplotypes and population genetic structures of seven mangrove species in China suggest historical connectivity between populations over a large geographic area. In contrast, significant genetic differentiation [FST = 0.165–0.629 (nSSR); GST = 0.173–0.923 (cpSSR)] indicates that populations of mangroves are isolated from one another with low levels of contemporary gene flow among populations. Our results suggest that populations of mangroves were historically more widely inter-connected and have recently been isolated, likely through a combination of ocean currents and human activities. In addition, genetic admixture in Beibu Gulf populations and populations surrounding Hainan Island and southern mainland China were attributed to asymmetric gene flow along prevailing oceanic currents in China in historical times. Even ocean currents promote genetic exchanges among mangrove populations, which are still unable to offset the effects of natural and anthropogenic fragmentation. The recent isolation and lack of gene flow among populations of mangroves may affect their long-term survival along the coastlines of South China. Our study enhances the understanding of oceanic currents contributing to population connectivity, and the effects of anthropogenic and natural habitat fragmentation on mangroves, thereby informing future conservation efforts and seascape genetics toward mangroves.

The structure and content of the database on the nucleotide sequences of BLV isolates improved with the use of information technologies

As a result of molecular genetic monitoring of bovine leukemia based on a set of methods (gene diagnostics - polymerase chain reaction (PCR), automatic sequencing; molecular phylogenetics) phylogenetic analysis presents the structure of an improved own replenished database (DB) for the characterized nucleotide sequences of the bovine leukemia virus (BLV), which includes information arrays contained in interconnected tables, which allows accumulating, storing, and combining all data through the formation of structured queries and reports with specified parameters in the database management system. At the same time, the results of the study are presented on the prevalence of BLV in the territories of some regions of Russia and Ukraine among the livestock; comparative analysis of genetic variants of the virus by genome loci: pol with clustering of the studied isolates into clade 1; env with the identification of 5 genotypes (GI (4%), GII (6%), GIV (79%), GVII (10%), GVIII (1%)) with the dominance of genotype IV (“European cluster”). In the course of the study, a low level of genetic variability among field isolates of BLV was established for the pol - 1.9% and env - 0.2-1.8% gene loci (depending on the genotype). This information product is registered in the register of databases: certificate of state registration No 2020620530 dated 23.03.2020.

Ecological Specialization and Evolutionary Reticulation in Extant Hyaenidae.

During the Miocene, Hyaenidae was a highly diverse family of Carnivora that has since been severely reduced to four species: the bone-cracking spotted, striped, and brown hyenas, and the specialized insectivorous aardwolf. Previous studies investigated the evolutionary histories of the spotted and brown hyenas, but little is known about the remaining two species. Moreover, the genomic underpinnings of scavenging and insectivory, defining traits of the extant species, remain elusive. Here, we generated an aardwolf genome and analyzed it together with the remaining three species to reveal their evolutionary relationships, genomic underpinnings of their scavenging and insectivorous lifestyles, and their respective genetic diversities and demographic histories. High levels of phylogenetic discordance suggest gene flow between the aardwolf lineage and the ancestral brown/striped hyena lineage. Genes related to immunity and digestion in the bone-cracking hyenas and craniofacial development in the aardwolf showed the strongest signals of selection, suggesting putative key adaptations to carrion and termite feeding, respectively. A family-wide expansion in olfactory receptor genes suggests that an acute sense of smell was a key early adaptation. Finally, we report very low levels of genetic diversity within the brown and striped hyenas despite no signs of inbreeding, putatively linked to their similarly slow decline in effective population size over the last ∼2 million years. High levels of genetic diversity and more stable population sizes through time are seen in the spotted hyena and aardwolf. Taken together, our findings highlight how ecological specialization can impact the evolutionary history, demographics, and adaptive genetic changes of an evolutionary lineage.

The role of gene flow and chromosomal instability in shaping the bread wheat genome.

Bread wheat (Triticum aestivum) is one of the world's most important crops; however, a low level of genetic diversity within commercial breeding accessions can significantly limit breeding potential. In contrast, wheat relatives exhibit considerable genetic variation and so potentially provide a valuable source of novel alleles for use in breeding new cultivars. Historically, gene flow between wheat and its relatives may have contributed novel alleles to the bread wheat pangenome. To assess the contribution made by wheat relatives to genetic diversity in bread wheat, we used markers based on single nucleotide polymorphisms to compare bread wheat accessions, created in the past 150 years, with 45 related species. We show that many bread wheat accessions share near-identical haplotype blocks with close relatives of wheat's diploid and tetraploid progenitors, while some show evidence of introgressions from more distant species and structural variation between accessions. Hence, introgressions and chromosomal rearrangements appear to have made a major contribution to genetic diversity in cultivar collections. As gene flow from relatives to bread wheat is an ongoing process, we assess the impact that introgressions might have on future breeding strategies.

Population genetics and evolutionary history of the endangered Eld\u2019s deer (Rucervus eldii) with implications for planning species recovery

Eld's deer (Rucervus eldii) with three recognised subspecies (R. e. eldii, R. e. thamin, and R. e. siamensis) represents one of the most threatened cervids found in Southeast Asia. The species has experienced considerable range contractions and local extinctions owing to habitat loss and fragmentation, hunting, and illegal trade across its distribution range over the last century. Understanding the patterns of genetic variation is crucial for planning effective conservation strategies. This study investigated the phylogeography, divergence events and systematics of Eld's deer subspecies using the largest mtDNA dataset compiled to date. We also analysed the genetic structure and demographic history of R. e. eldii using 19 microsatellite markers. Our results showed that R. e. siamensis exhibits two divergent mtDNA lineages (mainland and Hainan Island), which diverged around 0.2 Mya (95% HPD 0.1–0.2), possibly driven by the fluctuating sea levels of the Early Holocene period. The divergence between R. e. eldii and R. e. siamensis occurred around 0.4 Mya (95% HPD 0.3–0.5), potentially associated with the adaptations to warm and humid climate with open grassland vegetation that predominated the region. Furthermore, R. e. eldii exhibits low levels of genetic diversity and small contemporary effective population size (median = 7, 4.7–10.8 at 95% CI) with widespread historical genetic bottlenecks which accentuates its vulnerability to inbreeding and extinction. Based on the observed significant evolutionary and systematic distance between Eld’s deer and other species of the genus Rucervus, we propose to classify Eld's deer (Cervus eldii) in the genus Cervus, which is in congruent with previous phylogenetic studies. This study provides important conservation implications required to direct the ongoing population recovery programs and planning future conservation strategies.