Population Genetic Analyses Research Articles

Introgression drives adaptation to the plateau environment in a subterranean rodent

BackgroundIntrogression has repeatedly been shown to play an important role in the adaptation of species to extreme environments, yet how introgression enables rodents with specialized subterranean lifestyle to acclimatize to high altitudes is still unclear. Myospalacinae is a group of subterranean rodents, among which the high-altitude plateau zokors (Eospalax baileyi) and the low-altitude Gansu zokors (E. cansus) are sympatrically distributed in the grassland ecosystems of the Qinghai-Tibet Plateau (QTP). Together, they provide a model for the study of the role of introgression in the adaptation of low-altitude subterranean rodents to high altitudes.ResultsApplying low-coverage whole-genome resequencing and population genetics analyses, we identified evidence of adaptive introgression from plateau zokors into Gansu zokors, which likely facilitated the adaptation of the latter to the high-altitude environment of the QTP. We identified positively selected genes with functions related to energy metabolism, cardiovascular system development, calcium ion transport, and response to hypoxia which likely made critical contributions to adaptation to the plateau environment in both plateau zokors and high-altitude populations of Gansu zokors.ConclusionsIntrogression of genes associated with hypoxia adaptation from plateau zokors may have played a role in the adaptation of Gansu zokors to the plateau environment. Our study provides new insights into the understanding of adaptive evolution of species on the QTP and the importance of introgression in the adaptation of species to high-altitude environments.

Development and characterization of polymorphic microsatellite markers for Periplaneta americana (Blattodea: Blattidae).

The American cockroach, Periplaneta americana (Blattodea: Blattidae), is a prevalent urban pest with significant public health implications. This study aimed to develop and validate novel microsatellite markers to understand the genetic diversity and population genetic structure of P. americana. In this study, a total of 397,898 microsatellite markers were developed based on 24.6 million genomic DNA sequences. Twenty microsatellite markers were selected and amplified with varying numbers of alleles ranging from 0 to 35. Seven out of 20 markers were characterized for their polymorphism and amplification efficiency. The polymorphic information content (PIC) values of these markers were high (0.669 to 0.950) implying their effectiveness. These markers also revealed 7 to 35 alleles per locus across tested samples, highlighting their utility in assessing the extensive genetic variation within Periplaneta americana populations. These results provide insightful information that may be applied to the genetic analysis of the American cockroach population using the developed species-specific microsatellite marker.

Broad host use and frequent polyandry in the facultative dulotic species Formica aserva (Hymenoptera: Formicidae).

The study of social parasitism faces numerous challenges arising from the intricate and intranidal host-parasite interactions and the rarity of parasites compared to their free-living counterparts. As a result, our understanding of the ecology and evolution of most social parasites remains limited. Using whole-genome and reduced-representation sequence data, we conducted a study to fill knowledge gaps on host use, colony social structure, and population genetics of the facultative dulotic ant Formica aserva Forel. Our study reveals the remarkable ability of F. aserva to exploit at least 20 different host species across its wide geographic distribution. In some cases, one social parasite colony exploits multiple hosts simultaneously, suggesting a high degree of generalization even at a local spatial scale. Approximately 80% of the colonies were monogyne (with a single queen), with many exhibiting higher rates of polyandry compared to most Formica ants. Although we identified a supergene on chromosome 3, its association with colony structure remains uncertain due to the rarity of polygyny in our sample. Population genetic analyses reveal substantial geographic population structure, with the greatest divergence between California populations and those from the rest of the range. Mitochondrial population structure differs from structure inferred from the nuclear genome on a broad geographic scale, suggesting a possible role of adaptive introgression or genetic drift. This study provides valuable insights into the ecology and evolution of F. aserva, underscoring the need for further research to decipher the complexities of host interactions and the genetic mechanisms that regulate social structure.

Whole Genome Sequences of Cryptotympana Atrata Fabricius, 1775 (Hemiptera: Cicadidae) in the Korean Peninsula: Insights into Population Structure with Novel Pathogenic Or Symbiotic Candidates

Background: The blackish cicada (Cryptotympana atrata) exhibits unique characteristics and is one of the model cicadas found in the Korean Peninsula. It is a species of southern origin, prefers high temperatures, and is listed as a climate-sensitive indicator species in South Korea. Therefore, this species can be utilized to study the impact of climate change on the genetic diversity and structure of populations. However, research on the genome of C. atrata is limited. Methods: We sequenced the genome of an individual collected from South Korea and constructed a draft genome. Additionally, we collected ten specimens from each of the five regions in South Korea and identified single nucleotide variants (SNVs) for population genetic analysis. The sequencing library was constructed using the MGIEasy DNA Library Prep Kit and sequenced using the MGISEQ-2000 platform with 150-bp paired-end reads. Results: The draft genome of C. atrata was approximately 5.0 Gb or 5.2 Gb, making it one of the largest genomes among insects. Population genetic analysis, which was conducted on four populations in South Korea, including both previously distributed and newly expanded regions, showed that Jeju Island, a remote southern island with the highest average temperature, formed an independent genetic group. However, there were no notable genetic differences among the inland populations selected based on varying average temperatures, indicating that the current population genetic composition on the Korean Peninsula is more reflective of biogeographic history rather than climate- induced genetic structures. Additionally, we unexpectedly observed that most individuals of C. atrata collected in a specific locality were infected with microbes not commonly found in insects, necessitating further research on the pathogens within C. atrata. Conclusion: This study introduces the draft genome of C. atrata, a climate-sensitive indicator species in South Korea. Population analysis results indicate that the current genetic structure of C. atrata is driven by biogeographic history rather than just climate. The prevalence of widespread pathogen infections raises concerns about their impact on C. atrata. Considering the scarcity of publicly available genomic resources related to the family Cicadidae, this draft genome and population data of C. atrata are expected to serve as a valuable resource for various studies utilizing cicada genomes.

An integrative approach to the delineation of locally endemic species: A case study of Vitis baihuashanensis (Vitaceae) and its implication for conservation management

Species definition and classification have long been the subject of controversy, and name changes can often be a source of frustration for both conservationists and the public. Vitis baihuashanensis is a critically endangered grapevine endemic to Beijing with only two remaining wild individuals. Although formerly treated as a synonym of V. amurensis, it was later listed in the List of National Key Protected Wild Plants (LNKPWP) in 2021. Here, we evaluated the taxonomic identity of V. baihuashanensis based on phylogenomic inference and population genetic analysis, and tested the species boundaries under various major species concepts (biological, morphological, ecological, phylogenetic, and integrative species concepts). Phylogenetic inference revealed that the amurensis-baihuashanensis clade was monophyletic, samples of V. baihuashanensis nested within the V. amurensis node. Population genetic analysis demonstrated that V. baihuashanensis samples clustered with V. amurensis. Our findings from field observations, morphological comparisons, pollination experiments, and genetic analyses indicate that V. baihuashanensis and V. amurensis are the same species under the integrative species concept, and support the synonymy of V. baihuashanensis under V. amurensis. Given that V. baihuashanensis was listed in the LNKPWP, we suggest that it be removed in the next update of the list because of limited financial resources. Nevertheless, the two wild individuals deserve conservation attention because of their distinct leaf characteristics and potential of cold tolerance, which could have important applications in the horticulture and grape industries. Our study provides multiple lines of evidence for clarifying the identity of a taxonomically questionable species, as well as valuable suggestion with conservation and management implications.

The complete mitochondrial genome and microsatellite discovery of the Chilean kelp crab Taliepus dentatus (Brachuyra, Majoidea)

Abstract The complete sequence of the mitochondrial genome and fifteen microsatellite loci for the Chilean kelp crab Taliepus dentatus are reported for the first time. The DNA assembly obtained from an Illumina sequencing revealed a complete mitochondrial genome of 15 603 bp in length. The gene composition and arrangement were similar to that reported for most decapod crabs, containing 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes and a non-coding region. A phylogeny performed with 10 species obtained from GenBank placed T. dentatus close to individuals of the Family Epialtidae. From the 6397 repeated sequences encountered in the data, 15 microsatellite loci primers were designed and five tested for variability in specimens obtained from two sampling sites separated by 300 km of distance. The mean number of alleles per locus was nine (5–15 alleles per locus) and the observed heterozygosities ranged from 0.34 to 0.8. Departure from Hardy–Weinberg equilibrium was observed in two out of the five microsatellites, while none of the loci exhibited significant linkage disequilibrium. This genetic resource will be useful for phylogeny, population genetics and parentage analysis of the commercial species T. dentatus.

Genetic diversity and population structure of the semiterrestrial crab Armases benedicti (Brachyura, Sesarmidae) along the North Brazilian coast

Abstract For coastal marine species, gene flow patterns are intricately shaped by environmental factors such as oceanographic currents and river plumes. Despite these natural barriers, pelagic larval duration and salinity tolerance potentially facilitate the movement of individuals, resulting in panmixia. This study utilized Cox1 mtDNA data to conduct population genetics and structure analysis of the semiterrestrial crab Armases benedicti along the North Brazilian coast. The haplotype network displayed a star-like configuration, indicating recent mutation events and confirming minimal genetic structure. While DAPC analysis identified three distinct genetic clusters, limited genetic differentiation and negligible structuring were evident between Amapá, the northmost coastal Brazilian state, and Pará (approx. 400 km from the Amapá sampling site). Maranhão (approx. 600 km from Pará) exhibited higher Fst values in all pairwise comparisons but remained just one mutational step away from other sites. Despite coastal barriers affecting genetic connectivity, our findings suggest that A. benedicti populations demonstrate low genetic differentiation, hinting at the minimal impact of the Amazon plume as a barrier to gene flow, possibly due to the species’ adaptability to brackish environments. However, employing more informative genetic markers and conducting complementary ecological studies on larval salinity tolerance remain crucial for a deeper understanding of Armases population dynamics and adaptive strategies.

Population genetic structure and demographic history reconstruction of introduced flathead catfish (Pylodictis olivaris) in two US Mid-Atlantic rivers.

Population genetic analysis of invasive populations can provide valuable insights into the source of introductions, pathways for expansion, and their demographic histories. Flathead catfish (Pylodictis olivaris) are a prolific invasive species with high fecundity, long-distance dispersal, and piscivorous feeding habits that can lead to declines in native fish populations. In this study, we analyse the genetics of invasive P. olivaris in the Mid-Atlantic region to assess their connectivity and attempt to reconstruct the history of introduced populations. Based on an assessment across 13 microsatellite loci, P. olivaris from the Susquehanna River system (N = 537), Schuylkill River (N = 33), and Delaware River (N = 1) have low genetic diversity (global Hobs = 0.504), although we detected no evidence of substantial inbreeding (FIS = -0.083 to 0.022). P. olivaris from these different river systems were genetically distinct, suggesting separate introductions. However, population structure was much weaker within each river system and exhibited a pattern of high connectivity, with some evidence of isolation by distance. P. olivaris from the Susquehanna and Schuylkill rivers showed evidence for recent genetic bottlenecks, and demographic models were consistent with historical records, which suggest that populations were established by recent founder events consisting of a small number of individuals. Our results show the risk posed by small introductions of P. olivaris, which can spread widely once a population is established, and highlight the importance of prevention and sensitive early detection methods to prevent the spread of P. olivaris in the future.

Implementasi Teknologi Genetika Untuk Konservasi Spesies Laut Terancam: Tinjauan Literatur Tentang Metode dan Keberhasilan

The pace of global environmental change and the intensification of human activities have put significant pressure on marine ecosystems, threatening the sustainability of many species that are important both for ecosystems and the economies of coastal communities. In this context, this study aims to evaluate the application of genetic technologies in the conservation of endangered marine species, focusing on environmental DNA (eDNA) monitoring, CRISPR genetic engineering techniques and population genetic analysis. The method used was a literature review that examined current academic sources related to genetic technologies and their implementation in conservation. Findings show that eDNA is a highly effective tool in species and habitat monitoring, and has been successful in specific cases such as Napoleon fish and green turtles in Raja Ampat. In contrast, CRISPR techniques offer the potential to improve the genetic resilience of species, despite significant regulatory and ethical challenges. The implications of this study emphasize the need for strong policy support and international collaboration to address these challenges and optimize the use of genetic technologies in more effective conservation strategies in the future.

Local versus regional patterns in zoospore dispersal of the kelp Eisenia bicyclis (Laminariales, Phaeophyceae)

SummaryIt is generally accepted that kelp populations have a metapopulation structure. Most zoospores settle near to their parent individual, and infrequent but long‐distance dispersal of zoospores contributes to gene flow between local populations. Population genetic analysis of single nucleotide polymorphism genotyping by MIG‐seq (i.e. multiplexed inter‐simple sequence repeats genotyping by sequencing) was performed on the dominant kelp, Eisenia bicyclis, in two areas: Kitsunezaki (a sheltered area) and Shimoda (an exposed site). Regional scale analysis of genetic structure was conducted at six sites in Kitsunezaki and three sites in Shimoda. When viewed on a regional scale based on the inbreeding coefficient within the local population, the inbreeding ratio was higher in Shimoda than in Kitsunezaki, probably as a result of the limited vertical zonal distribution in the exposed environment. Vertically wide distribution in the sheltered environment apparently enabled frequent crossing among individuals in Kitsunezaki. By contrast, when viewed on a local scale based on the pairwise kinship coefficient (FST) between populations, gene flow among local populations in Shimoda occurred over a wide area, but was limited in Kitsunezaki. In Shimoda, genetic exchange between local populations, even if inbreeding is locally active, is likely to support metapopulation maintenance and rapid recovery of local populations. In Kitsunezaki, however, genetic exchange among local populations is limited within few 100 m, and the metapopulation structure will decline in the long term because of inbreeding depression. Local dispersal distance of zoospores was investigated based on parent–offspring analysis in the Kitsunezaki population, which revealed that zoospores mainly settled within 5 m of their parent. However, some zoospores traveled over 27 m within the 4 × 30 m study area. The present study shows the importance of examination at different spatial scales when investigating zoospore dispersal of laminarialean kelps.

Genetic polymorphisms of common sandflies in selected areas of Henan Province based on DNA barcoding

To characterize the species of common sandflies in Henan Province using DNA barcoding with cytochrome c oxidase subunit I (COI) gene as the molecular marker, and to analyze the genetic polymorphisms of sandflies, so as to provide insights into visceral leishmaniasis prevention and control in Henan Province. Sandfly specimens were sampled from 13 sandflies surveillance sites from 2021 to 2023 in Anyang City, Zhengzhou, Luoyang and Xuchang cities (Zhengzhou-Luoyang-Xuchang areas) where visceral leishmaniasis cases were reported and in Jiaozuo and Xinxiang cities (Jiaozuo-Xinxiang areas) without visceral leishmaniasis cases reported. Genomic DNA was extracted from a single sandfly, and COI gene was amplified. The amplification product was subjected to bidirectional sequencing. Following sequence assembly, the species of sandflies was characterized through sequence alignment using the BLAST tool. The intra-specific and inter-specific genetic distances of sandflies were estimated among different areas using the software Mega 11, and phylogenetic trees were created. The polymorphisms of nucleotide sequences in the sandflies COI gene were estimated using the software DnaSP. The fixation index (FST) of different geographical isolates of sandflies was calculated using the Arlequin software, and the gene flow value (Nm) was used to measure the gene flow in the sandflies populations. In addition, the population genetic structure of different geographical populations of Phlebotomus chinensis was analyzed using the STRUCTURE software. A total of 978 sandflies were collected from 13 sandflies surveillance sites in Zhengzhou-Luoyang-Xuchang areas, Jiaozuo-Xinxiang areas and Anyang City of Henan Province from 2021 to 2023, and 475 sandflies were randomly sampled for subsequent detections. A total of 304 Ph. chinensis, 162 Se. squamirostris and 9 Se. bailyi were identified based on molecular biological detection of the COI gene, and Se. bailyi was reported for the first time in Henan Province. The intraspecific genetic distances of sandflies were 0.000 to 0.040, and the inter-specific genetic distances ranged from 0.133 to 0.161. Phylogenetic analysis revealed that each of the three sandfly species was clustered into a clade. The genetic polymorphisms of Ph. chinensis populations varied among different areas, with the highest haplotype diversity (0.966 ± 0.007) and the greatest nucleotide diversity (0.011) in Zhengzhou-Luoyang-Xuchang areas, and the lowest haplotype diversity (0.720 ± 0.091) and nucleotide diversity (0.004) in Anyang City. The dominant haplotype of Ph. chinensis populations was Pch_Hap_2 in Anyang City and Jiaozuo-Xinxiang areas, with moderate genetic differentiation (0.05 < FST < 0.15) and frequent gene exchange (Nm value > 1) between Ph. chinensis populations sampled from Anyang City, and Jiaozuo-Xinxiang areas. Population genetic structure analysis showed that the dominant component of Ph. chinensis populations was K5 in Anyang City and Jiaozuo-Xinxiang areas. No obvious dominant haplotype was observed in Ph. chinensis populations sampled from Zhengzhou-Luoyang-Xuchang areas, which had very high genetic differentiation (FST > 0.25) and little gene exchange (Nm value < 1) with Ph. chinensis populations from Anyang City, and Jiaozuo-Xinxiang areas, with K3 as the dominant component. In addition, there was no significant difference in the genetic polymorphism level among Se. squamirostris populations from the three areas. There are Ph. chinensis, Se. squamirostris and Se. bailyi in Henan Province, and S. bailyi is recorded for the first time in Henan Province by molecular biological assays. There are different levels of genetic differentiation and gene exchange among P. chinensis populations in different areas of Henan Province.

Phenotypic correlates between clock genes and phenology among populations of Diederik cuckoo, Chrysococcyx caprius.

The Diederik cuckoo, Chrysococcyx caprius, is a small Afrotropical bird in the family Cuculidae. It is taxonomically related to 13 other species within the genus Chrysococcyx and is migratory in sub-Saharan Africa. It has a unique breeding behaviour of being a brood parasite: Breeding pairs lay their eggs in the nests of a host species and hatchlings expel the eggs of the host species. The aim of the present study was to investigate diversity in two circadian clock genes, Clock and Adcyap1, to probe for a relationship between genetic polymorphisms and their role in circannual timing and habitat selection (phenology) in intra-African migrants. DNA extracted from blood was used for the PCR amplification and sequencing of clock genes in 30 Diederik cuckoos. Three alleles were detected for Clock with similar genotypes between individuals from the Northern and Southern breeding ranges while 10 alleles were detected for Adcyap1, having shorter alleles in the North and longer alleles in the South. Population genetic analyses, including allele frequency and zygosity analysis, showed distinctly higher frequencies for the most abundant Clock allele, containing 10 polyglutamine repeats, as well as a high degree of homozygosity. In contrast, all individuals were heterozygous for Adcyap1 and alleles from both regions showed distinct differences in abundance. Comparisons between both clock genes and phenology found several phenotypic correlations. This included evidence of a relationship between the shorter alleles and habitat selection as well as a relationship between longer alleles and timing. In both instances, evidence is provided that these effects may be sex-specific. Given that these genes drive some of the synchronicity between environments and the life cycles of birds, they provide valuable insight into the fitness of species facing global challenges including climate change, urbanisation and expanding agricultural practices.

Genetic diversity and population structure of an insect-pollinated and bird-dispersed dioecious tree Magnolia kwangsiensis in a fragmented karst forest landscape.

This study combined population genetics and parentage analysis to obtain foundational data for the conservation of Magnolia kwangsiensis. M. kwangsiensis is a Class I tree species that occurs in two disjunct regions in a biodiversity hotspot in southwest China. We assessed the genetic diversity and structure of this species across its distribution range to support its conservation management. Genetic diversity and population structure of 529 individuals sampled from 14 populations were investigated using seven nuclear simple sequence repeat (nSSR) markers and three chloroplast DNA (cpDNA) fragments. Parentage analysis was used to evaluate the pollen and seed dispersal distances. The nSSR marker analysis revealed a high genetic diversity in M. kwangsiensis, with an average observed (Ho) and expected heterozygosities (He) of 0.726 and 0.687, respectively. The mean and maximum pollen and seed dispersal distances were 66.4 and 95.7 m and 535.4 and 553.8 m, respectively. Our data revealed two distinct genetic groups, consistent with the disjunct geographical distribution of the M. kwangsiensis populations. Both pollen and seed dispersal movements help maintain genetic connectivity among M. kwangsiensis populations, contributing to high levels of genetic diversity. Both genetically differentiated groups corresponding to the two disjunct regions should be recognized as separate conservation units.

Are There Barriers Separating the Pink River Dolphin Populations (Inia boliviensis, Iniidae, Cetacea) within the Mamoré-Iténez River Basins (Bolivia)? An Analysis of Its Genetic Structure by Means of Mitochondrial and Nuclear DNA Markers.

The pink river dolphin, or bufeo, is one of the dolphins which lives in the rivers of the Orinoco and Amazon basins in South America. The Bolivian bufeo population is considered a differentiated species (Inia boliviensis) from the Amazon and Orinoco species (Inia geoffrensis). Until now, no study has completed an extensive population genetics analysis of the bufeo in Bolivian rivers. We analyzed 82 bufeos from different rivers from the Mamoré and Iténez (Guaporé) river basins for the mt control region (CR), nuclear microsatellites, and DQB-1 gene sequences to determine if the inner rapids of these Bolivian river basins have some influence on the genetic structure of this species. The first relevant result was that the genetic diversity for CR, and the microsatellites were substantially lower in the Bolivian bufeos than in the dolphins studied in other areas of the Amazon and Orinoco. However, the DQB-1 gene sequences yielded similar genetic diversity to those found in other areas. The second relevant result is the existence of some significant genetic heterogeneity among the bufeo populations within Bolivia, although in a small degree, but this differentiation is independent of the inner rapids of the Bolivian rivers we sampled. The third relevant result was the existence of significant isolation by distance for the CR, but not for microsatellites and DQB-1 gene sequences. This was related to differential gene flow capacity of females (philopatric) and males (less philopatric and more migrants) and, possibly, to different selective patterns affecting the molecular markers studied. The fourth relevant result was related to diverse demographic changes of these bufeos. At least two or three bottleneck events and one or two population expansions have occurred in the Bolivian bufeo population. The major part of these events occurred during the Pleistocene.

Whole-genome resequencing identifies candidate genes associated with heat adaptation in chickens

The wide distribution and diverse varieties of chickens make them important models for studying genetic adaptation. The aim of this study was to identify genes that alter heat adaptation in commercial chicken breeds by comparing genetic differences between tropical and cold-resistant chickens. We analyzed whole-genome resequencing data of 186 chickens across various regions in Asia, including the following breeds: Bian chickens (B), Dagu chickens (DG), Beijing-You chickens (BY), and Gallus gallus jabouillei from China; Gallus gallus murghi from India; Vietnam native chickens (VN); Thailand native chickens (TN) and Gallus gallus spadiceus from Thailand; and Indonesia native chickens (IN), Gallus gallus gallus, and Gallus gallus bankiva from Indonesia. In total, 5,454,765 SNPs were identified for further analyses. Population genetic structure analysis revealed that each local chicken breed had undergone independent evolution. Additionally, when K = 5, B, BY, and DG chickens shared a common ancestor and exhibited high levels of inbreeding, suggesting that northern cold-resistant chickens are likely the result of artificial selection. In contrast, the runs of homozygosity (ROH) and the ROH-based genomic inbreeding coefficient (FROH) results for IN, TN, and VN chickens showed low levels of inbreeding. Low population differentiation index values indicated low differentiation levels, suggesting low genetic diversity in tropical chickens, implying increased vulnerability to environmental changes, decreased adaptability, and disease resistance. Whole-genome selection sweep analysis revealed 69 candidate genes, including LGR4, G6PC, and NBR1, between tropical and cold-resistant chickens. The genes were further subjected to GO and KEGG enrichment analyses, revealing that most of the genes were primarily enriched in biological synthesis processes, metabolic processes, central nervous system development, ion transmembrane transport, and the Wnt signaling pathway. Our study identified heat adaptation genes and their functions in chickens that primarily affect chickens in high-temperature environments through metabolic pathways. These heat-resistance genes provide a theoretical basis for improving the heat-adaptation capacity of commercial chicken breeds.

Genetic network analysis uncovers spatial variation in diversity and connectivity of a species presenting a continuous distribution

The conservation of genetic diversity and connectivity is essential for the long-term persistence and adaptive ability of a species. Recent calls have been made for the inclusion of genetic diversity and differentiation measures in the assessment, management, and conservation of species. However, the literature often lacks direction on how to do so for species with continuous distributions or no distinct breaks in genetic connectivity. There are many considerations to overcome when investigating genetic diversity and connectivity of such species. We combine multiple genetic network methodologies with more traditional population genetic analyses within a single framework to address the challenges of investigating population structure and quantifying variation in genetic diversity and connectivity of wide-ranging species with continuous distributions. We demonstrate the efficacy and applicability of our framework through a study on woodland caribou (Rangifer tarandus) occupying the boreal forest of Canada; a species of significant conservation concern. The dataset consisted of 4911 unique individuals genotyped at 9 microsatellite loci, which were subsequently partitioned into 103 spatial nodes to create a population-based genetic network. The Walktrap community detection algorithm was used to detect hierarchical population genetic structure within the study area and node-based network metrics such as mean inverse edge weight and clustering coefficient were used to quantify the variation in genetic connectivity across the range. Lastly, genetic diversity was assessed by calculating allelic richness and heterozygosity of the nodes making up the network. The community detection analysis identified two communities at the coarsest scale to nine communities at the optimal partition. A strong pattern of Isolation by Distance (IBD) was found across the range at multiple scales. Furthermore, signs of genetic erosion along the study area’s southern boundaries were depicted by nodes presenting low genetic diversity and low centrality values. These results are important to the species status assessments in providing previously unavailable information on connectivity and diversity within and beyond the current local population units used in management. Our approach to quantify the patterns and extent of connectivity across the boreal range is comprehensive and could easily be adapted to other species. The results are robust and provide a solid foundation for the continued monitoring and recovery of the species.

Fruiting Characteristics and Molecular-Assisted Identification of Korla Fragrant Pear Bud Mutation Materials

Korla fragrant pear is a high-quality local pear variety native to Xinjiang, China. Currently, the low fruit-setting rate and low calyx shedding rate problems in Korla fragrant pears have been highlighted, which seriously affect the fruit yield and quality. It is of great significance to research the fruiting characteristics and molecular-assisted identification of Korla fragrant pear bud mutation materials for enriching the germplasm resources of Korla fragrant pear. In this research, a natural pollination group (YB) of Korla fragrant pear bud mutation materials and a natural pollination group (CK) of Korla fragrant pears were established. On the fruiting characteristics, the fruit-setting rate and calyx-removal rate of the two groups were investigated. In terms of fruit quality, the fruit shape index, fruit specific gravity, soluble solids content, sugar:acid ratio, soluble sugar content, and other indicators were measured. For the anatomical structure of the calyx tube, the detachment cells were observed. The formation time of the two groups of detached cells was compared. In the GBS simplified genome sequencing, a phylogenetic tree was constructed based on the obtained SNP sites. A principal component analysis, population genetic structure analysis, and genetic diversity index analysis were carried out. In the aspect of SSR molecular marker identification, the SSR types were counted. Polyacrylamide gel electrophoresis was performed. The results demonstrate the following: (1) the fruit-setting rate (30.87%) and calyx-removal rate (68.11%) in the YB group were significantly higher than those in the CK group (19.37%) and the calyx-removal rate (55.18%). (2) There was no significant difference in fruit quality indexes, such as average fruit weight (127.10–130.00 g) and soluble sugar content (9.47–9.56%) between the two groups. (3) Abscission-layer cells were observed at 2, 4, 6, 8, and 10 h after calyx tube discoloration in the YB group and at 48, 72, and 96 h after calyx tube discoloration in the CK group. (4) The genetic background of the YB group and the CK group was similar at the GBS level, but there were differences at the DNA level. This research finally shows that Korla fragrant pear bud mutation material is a good germplasm resource. This germplasm resource can promote the structural optimization of Korla fragrant pear varieties and the healthy development of the industry.

A Protocol to Extract a Specific Genomic Region from a Public Whole-Genome Database and Modify Analytical Bin Length for Population Genetic Studies.

With the advent of "next-generation" sequencing and the continuous reduction in sequencing costs, an increasing amount of genomic data has emerged, such as whole-genome, whole-exome, and targeted sequencing data. These applications are popular not only in mega sequencing projects, such as the 1000 Genomes Project and UK BioBank, but also among individual researchers. Evolutionary genetic analyses, such as the dN/dS ratio and Tajima's D, are demanded more and more for whole-genome-level population data. These analyses are often carried out under a uniform custom bin size across the genome. However, these analyses require subdivision of a genomic region into functional units, such as protein-coding regions, introns, and untranslated regions, and computing these genetic measures for large-scale data remains challenging. In a recent investigation, we successfully devised a method to address this issue. This method requires a multi-sample VCF file containing population data, a reference genome, target regions in the BED file, and a list of samples to be included in the analysis. Given that the targeted regions are extracted in a new VCF file, targeted population genetic analysis can be performed. We conducted Tajima's D analysis using this approach on intact and pseudogenes, as well as non-coding regions.

Morphological Structure Identification, Comparative Mitochondrial Genomics and Population Genetic Analysis toward Exploring Interspecific Variations and Phylogenetic Implications of Malus baccata 'ZA' and Other Species.

Malus baccata, a valuable germplasm resource in the genus Malus, is indigenous to China and widely distributed. However, little is known about the lineage composition and genetic basis of 'ZA', a mutant type of M. baccata. In this study, we compared the differences between 'ZA' and wild type from the perspective of morphology and ultrastructure and analyzed their chloroplast pigment content based on biochemical methods. Further, the complete mitogenome of M. baccata 'ZA' was assembled and obtained by next-generation sequencing. Subsequently, its molecular characteristics were analyzed using Geneious, MISA-web, and CodonW toolkits. Furthermore, by examining 106 Malus germplasms and 42 Rosaceae species, we deduced and elucidated the evolutionary position of M. baccata 'ZA', as well as interspecific variations among different individuals. In comparison, the total length of the 'ZA' mitogenome (GC content: 45.4%) is 374,023 bp, which is approximately 2.33 times larger than the size (160,202 bp) of the plastome (GC: 36.5%). The collinear analysis results revealed abundant repeats and genome rearrangements occurring between different Malus species. Additionally, we identified 14 plastid-driven fragment transfer events. A total of 54 genes have been annotated in the 'ZA' mitogenome, including 35 protein-coding genes, 16 tRNAs, and three rRNAs. By calculating nucleotide polymorphisms and selection pressure for 24 shared core mitochondrial CDSs from 42 Rosaceae species (including 'ZA'), we observed that the nad3 gene exhibited minimal variation, while nad4L appeared to be evolving rapidly. Population genetics analysis detected a total of 1578 high-quality variants (1424 SNPs, 60 insertions, and 94 deletions; variation rate: 1/237) among samples from 106 Malus individuals. Furthermore, by constructing phylogenetic trees based on both Malus and Rosaceae taxa datasets, it was preliminarily demonstrated that 'ZA' is closely related to M. baccata, M. sieversii, and other proximate species in terms of evolution. The sequencing data obtained in this study, along with our findings, contribute to expanding the mitogenomic resources available for Rosaceae research. They also hold reference significance for molecular identification studies as well as conservation and breeding efforts focused on excellent germplasms.

Assessment of the genetic similarity between the novoaltayskaya horse breed and the original breeds by microsatellite DNA loci

The research was carried out for the purpose of a comparative assessment of the allele pool of the Novoaltayskaya horse breed and the breeds that participated in its creation. The experimental sample included 5736 horses, including: Novoaltayskaya breed – 363, Altai – 39, Lithuanian Heavy Draft – 159, Russian Heavy Draft – 617, Soviet d Heavy Draft – 288, Orlov trotter – 4,177, Budenny – 93. Population genetic analysis was performed using generally accepted methods. The following indicators were determined: the total number of alleles at 17 loci, the average number of alleles per locus, the level of polymorphism, observed and expected heterozygosity, coefficients of intrapopulation inbreeding, genetic similarity and genetic distances. It was established that horses of the Novo-Altai breed had the highest level of genetic diversity (154 alleles) and polymorphism (Ae = 4,909). Analysis of genetic differentiation showed the absence of intrapopulation inbreeding in the groups of Altai, Lithuanian Heavy Draft and Budenny breeds. Groups of horses of the Novoaltayskaya, Orlov trotter, Russian Heavy Draft and Soviet Heavy Draft breeds were distinguished by a slight deficiency of heterozygotes. It has been established that horses of the Novoaltayskaya and Heavy Draft breeds are characterized by a high frequency of occurrence of the HTG6 O allele, and the Altai breed is characterized by a high frequency of occurrence of the HTG4 M allele. A number of loci of alleles identical in spectrum to those of the Altai, Russian Heavy Draft and Soviet Heavy Draft breeds were identified in the Novoaltayskaya horse. Cluster analysis demonstrated a high level of genetic similarity of horses of the Novoaltayskaya breed with the Russian Heavy Draft (0,903) and Altai (0,899) breeds. As part of the study, using molecular genetic markers, new data was obtained on horses of seven breeds, with the help of which it is possible to improve breeding programs in horse breeding, allowing to control the biodiversity and genetic similarity of populations, preserving the originality and heterogeneity of the allele pool of horses of different breeds.