Genomic Polymorphism Research Articles

Investigation of Polymorphisms Induced by the Solo Long Terminal Repeats (Solo-LTRs) in Porcine Endogenous Retroviruses (ERVs).

Homologous recombination events take place between the 5' and 3' long terminal repeats (LTRs) of ERVs, resulting in the generation of solo-LTR, which can cause solo-LTR-associated polymorphism across different genomes. In the current study, specific criteria were established for the filtration of solo-LTRs, resulting in an average of 5630 solo-LTRs being identified in 21 genomes. Subsequently, a protocol was developed for detecting solo-LTR polymorphisms in the pig genomes, resulting in the discovery of 927 predicted solo-LTR polymorphic sites. Following verification and filtration processes, 603 highly reliable solo-LTR polymorphic sites were retained, involving 446 solo-LTR presence sites (solo-LTR+) and 157 solo-LTR absence sites (solo-LTR-) relative to the reference genome. Intersection analysis with gene/functional regions revealed that 248 solo-LTR- sites and 23 solo-LTR+ sites overlapped with genes or were in the vicinity of genes or functional regions, impacting a diverse range of gene structures. Moreover, through the utilization of 156 solo-LTR polymorphic sites for population genetic analysis, it was observed that these solo-LTR loci effectively clustered various breeds together, aligning with expectations and underscoring their practical utility. This study successfully established a methodology for detecting solo-LTR polymorphic sites. By applying these methods, a total of 603 high-reliability solo-LTR polymorphic sites were pinpointed, with nearly half of them being linked to genes or functional regions.

Genomic Single Nucleotide Polymorphism (SNP) markers and mitochondrial haplotypes illuminate the origins of Crown-of-Thorns Starfish (Acanthaster solaris) outbreaks in the South China Sea

BackgroundOutbreaks of the coral predator Crown-of-Thorns Starfish (CoTS) pose a severe threat to coral reefs in the Indo-Pacific Ocean. In 2018, the South China Sea (SCS) experienced significant CoTS outbreaks, leading to extensive coral mortality across the Xisha, Zhongsha, Dongsha, and Nansha Islands, severely impacting the coral reef ecosystem.ResultsTo explore the origins of these outbreaks, we conducted a comprehensive genomic analysis using data from genomic single nucleotide polymorphism sites (SNPs) and mitochondrial haplotypes. Our analysis reveals that CoTS populations in the SCS, which exhibit moderate genetic diversity and may have undergone positive selection or population expansion. There was limited genetic differentiation among CoTS populations from XS, ZS, and NS groups. Especially between the XS and ZS groups, there was almost no genetic differentiation. The populations from XS, ZS, and NS groups have strong genetic connections with populations in Vietnam and the Philippines. There was high gene flow from Vietnam to the Xisha Islands and from the Philippines to the Nansha Islands, suggesting that the CoTS populations in these regions primarily originate from these neighboring countries.ConclusionThe comprehensive analyses of SNP and mitochondrial genomes have provided valuable insights into the population genetics of CoTS. This research has generated significant genomic resources and facilitated important studies on the genetics of the CoTS species. By identifying potential source populations and understanding the genetic basis of their spread, managers can develop more effective conservation strategies to protect vulnerable coral reef ecosystems in the SCS.

Somy evolution in the honey bee infecting trypanosomatid parasite, Lotmaria passim.

Lotmaria passim is a ubiquitous trypanosomatid parasite of honey bees nestled within the medically important subfamily Leishmaniinae. Although this parasite is associated with honey bee colony losses, the original draft genome-which was completed before its differentiation from the closely related Crithidia mellificae-has remained the reference for this species despite lacking improvements from newer methodologies. Here we report the updated sequencing, assembly, and annotation of the BRL type strain (ATCC PRA-422) of Lotmaria passim. The nuclear genome assembly has been resolved into 31 complete chromosomes and is paired with an assembled kinetoplast genome consisting of a maxicircle and 30 minicircle sequences. The assembly spans 33.7 Mb and contains very little repetitive content, from which our annotation of both the nuclear assembly and kinetoplast predicted 10,288 protein-coding genes. Analyses of the assembly revealed evidence of a recent chromosomal duplication event within chromosomes 5 and 6 and provides evidence for a high level of aneuploidy in this species, mirroring the genomic flexibility employed by other trypanosomatids as a means of adaptation to different environments. This high-quality reference can therefore provide insights into adaptations of trypanosomatids to the thermally regulated, acidic, and phytochemically rich honey bee hindgut niche, which offers parallels to the challenges faced by other Leishmaniinae during the challenges they undergo within insect vectors, during infection of mammals, and exposure to antiparasitic drugs throughout their multi-host life cycles. This reference will also facilitate investigations of strain-specific genomic polymorphisms, their role in pathogenicity, and the development of treatments for pollinator infection.

Genomic evidence of Escherichia coli gut population diversity translocation in leukemia patients.

Escherichia coli, a commensal species of the human gut, is an opportunistic pathogen that can reach extra-intestinal compartments, including the bloodstream and the bladder, among others. In non-immunosuppressed patients, purifying or neutral evolution of E. coli populations has been reported in the gut. Conversely, it has been suggested that when migrating to extra-intestinal compartments, E. coli genomes undergo diversifying selection as supported by strong evidence for adaptation. The level of genomic polymorphism and the size of the populations translocating from gut to extra-intestinal compartments is largely unknown. To gain insights into the pathophysiology of these translocations, we investigated the level of polymorphism and the evolutionary forces acting on the genomes of 77 E. coli isolated from various compartments in three immunosuppressed patients. Each patient had a unique strain, which was a mutator in one case. In all instances, we observed that translocation encompasses much of the genomic diversity present in the gut. The same signature of selection, whether purifying or diversifying, and as anticipated, neutral for mutator isolates, was observed in both the gut and bloodstream. Additionally, we found a limited number of non-specific mutations among compartments for non-mutator isolates. In all cases, urine isolates were dominated by neutral selection. These findings indicate that substantial proportions of populations are undergoing translocation and that they present a complex compartment-specific pattern of selection at the patient level.IMPORTANCEIt has been suggested that intra and extra-intestinal compartments differentially constrain the evolution of E. coli strains. Whether host particular conditions, such as immunosuppression, could affect the strain evolutionary trajectories remains understudied. We found that, in immunosuppressed patients, large fractions of E. coli gut populations are translocating with variable modifications of the signature of selection for commensal and pathogenic isolates according to the compartment and/or the patient. Such multiple site sampling should be performed in large cohorts of patients to gain a better understanding of E. coli extra-intestinal diseases.

Polymorphic insertions of DcSto miniature inverted-repeat transposable elements reveal genetic diversity structure within the cultivated carrot.

Miniature inverted-repeat transposable elements (MITEs) are a potent source of polymorphisms in plant genomes. A genotyping system, named DcS-ILP, based on polymorphic insertions of Stowaway MITEs (DcStos) localized in introns and identified in the reference genome DH1, has been developed for carrot. Here, we report an extension of the DcS-ILP genotyping system by incorporation of non-reference insertions identified in resequenced genomes representing the eastern gene pool. We genotyped 52 carrot accessions representing the eastern and western carrot gene pools with 92 markers developed previously (western DcS-ILP panel) together with 84 newly developed markers (eastern DcS-ILP panel). Overall, the DcS-ILP markers revealed a highly structured genetic diversity separating the eastern and the western carrot accessions at K = 2 and differentiating Indian breeding lines from the eastern accessions at K = 3. The eastern DcS-ILP panel proved to be more robust with respect to the eastern carrot gene pool, while it provided little information on the western accessions, as many of the DcSto insertions present in the eastern gene pool were absent in the western gene pool. As the western carrot accessions represent improved cultivars, DcSto insertional polymorphisms allowed detection of a selection-driven bottleneck at the improvement stage. Selection in the course of the improvement stage generally operated on standing variation, as the subset of DcSto insertions present in the western carrot likely originated from transposition events preceding the separation of both gene pools. However, occasional frequency shifts in the opposite direction were also revealed, possibly indicating selection for favorable variants associated with DcSto insertions.

Whole genome sequencing of M. tuberculosis for disease control in high-burden settings: study protocol for a cluster randomized controlled trial evaluating different community-wide intervention strategies in rural Madagascar

BackgroundRetrospective and descriptive molecular epidemiology studies have shown that Mycobacterium tuberculosis whole genome sequencing can identify outbreaks and disease transmission events with higher resolution than conventional epidemiological investigations. Those studies have strengthened our understanding of genomic polymorphisms correlating with person-to-person transmission and helped resolve putative transmission clusters. To date, systematic genomic surveillance programs implemented for M. tuberculosis were only implemented in low-incidence settings. The purpose of this study is to determine whether there is an impact of routine M. tuberculosis whole genome sequencing on tuberculosis case detection in a high-incidence setting.MethodsA cluster randomized controlled trial will be performed. Forty-eight rural village groups (or Fokontany) in the Vohibato district of Madagascar will be randomized to one of three interventions arms. Arm 1 (standard of care) involves healthcare facility-based passive case detection with smear microscopy testing. Arm 2 (best practice) consists of active case finding and Xpert MTB/RIF Ultra PCR testing followed by household contact investigations. Arm 3 (novel intervention) includes the same interventions as arm 2, with addition of sputum culture and M. tuberculosis whole genome sequencing for all newly diagnosed cases. In arm 3, molecular suggested putative outbreaks are investigated, and additional TB suspects are appropriately tested. The intervention observational period will be 2 years. The primary outcome will be the number of detected cases/100,000/year in each arm after 1 year of intervention.DiscussionThis study is designed to determine whether there is an impact of prospective whole genome sequencing-based molecular typing on tuberculosis case detection in high-incidence settings. Investigating potential outbreaks and focusing active case finding in spatiotemporal settings where disease transmission is suggested by genomic typing is hypothesized to improve case detection in rural communities.Trial registrationClinicalTrials.gov NCT05406453. Retrospectively registered on June 6, 2022.

Factors contributing to organelle genomes size variation and the intracellular DNA transfer in Polygonaceae

The use of complete organelle genomes, including chloroplast and mitochondrial genomes, is a powerful molecular method for studying biological evolution and gene transfer. However, in the case of Polygonaceae, an important family with numerous edible, medicinal, and ornamental species, the mitochondrial genomes of only three species have been sequenced and analyzed. In this study, we present the mitochondrial and chloroplast genomes of two important Tibetan medicinal plants, Bistorta viviparum and B. macrophyllum. All the organelle genomes are assembled into a single circular structure and contain a common set of 32 protein-coding genes (PCGs). Some genes such as rps2 and ndhF were found to have high nucleotide polymorphism (Pi) in the chloroplast genomes, while cox1, mttB and rps12 showed pronounced Pi values in the mitochondrial genomes. Furthermore, our analysis revealed that most chloroplast genes and mitochondrial PCGs in Polygonaceae plants are under purifying selection. However, a few genes, including the chloroplast gene psaJ and the mitochondrial genes ccmFc, atp8 and nad4, showed positive selection in certain Polygonaceae plants, as indicated by a Ka/Ks ratio greater than one. Structural variation analysis revealed a wealth of differences between the mitochondrial genomes of five Polygonaceae species, with a particularly notable large-scale inversion observed between Reynoutria japonica and Fallopia aubertii. Furthermore, an analysis of the homologous sequences in the chloroplast and mitochondrial genomes revealed that the rps7 has been transferred from the chloroplast to the mitochondrial genome in all five Polygonaceae species. Finally, ecological niche models were constructed for B. viviparum and B. macrophyllum, indicating that mean annual temperature and altitude are the main climatic factors influencing the distribution of both species. Although the current distribution of B. viviparum is significantly wider than that of B. macrophyllum, projections suggest that the optimal growth ranges of both species will expand in the future, with B. macrophyllum potentially exceeding B. viviparum. This study not only contributes to the plastid genome database for Polygonaceae plants, but also provides theoretical insights into the adaptive evolution of these plants.

Genetic structure and common ancestry expose the dingo-dog hybrid myth

Abstract The evolutionary history of canids has been shown to be complex, with hybridization and domestication confounding our understanding of speciation among various canid lineages. The dingo is a recent canid lineage that was completely isolated from other canids for over 5000 years on the Australian mainland, but the introduction of domestic dogs in 1788 has placed doubt on its independence, with recent studies highlighting hybridization between dingoes and domestic dogs. Using genomic single nucleotide polymorphism data from 434 Australian canid samples, we explicitly test for introgression between closely related canid groups and dingoes. We found no evidence of introgression between dingoes and domestic dogs and show that previous work has likely mischaracterized shared ancestral genetic variation as evidence for hybridization. Further, New Guinea Singing Dogs are the only canid group that significantly shared genetic variation with dingoes, which fits with our understanding of previous phylogenetic analyses. Despite more recent sympatric distributions with dogs, dingoes have likely maintained their independence since their arrival in Australia, even in areas with high lethal control, indicating that their evolutionary trajectory is currently being conserved. The future conservation of the dingo lineage will require policies that promote coexistence pathways between humans and dingoes that protect rangeland systems and the dingoes’ evolutionary future.

Genome-wide species delimitation and quantification of the extent of introgression in eriophyoid mite Epitrimerus sabinae complex (Acariformes: Eriophyoidea)

Species complex hinders the exploration of terrestrial species diversity, particularly in small arthropod lineages that are morphologically indistinguishable from each other. The Epitrimerus sabinae complex in the Eriophyoidea provides a valuable case study in species complex delimitation, as they exhibit limited morphological variations. In this study, we obtained thousands of nuclear genomic single-nucleotide polymorphisms via whole-genome sequencing from 55 E. sabinae complex specimens, covering their potential all known distribution ranges. We implemented a framework to infer cryptic speciation, which involved phylogenetic and genetic clustering to identify potential species, followed by population demographic assessment to confirm lineage independence (and thus species status). Our results demonstrate that the E. sabinae complex comprises ten distinct species. These species range from highly divergent, genetically isolated lineages, to differentiated populations involving gene flow. This gene flow is widespread across species boundaries, indicating potential genetic introgression among them. Additionally, demographic analyses revealed that the ten species have followed unique trajectories in size change during the Quaternary period. Time-calibrated phylogenies further showed that speciation in the E. sabinae complex occurred rapidly, resulting in a rapid radiation during the Neogene period. Collectively, parallelism/convergence and recent divergence involving multiple gene flows may explain the homoplasy of E. sabinae complex. Our results highlight the integrated approach in species complex delimitation.

Genomic and phenotypic polymorphism of Clostridium botulinum Group II strain Beluga through laboratory domestication

Laboratory domestication is the result of genetic and physiological changes of organisms acquired during numerous passages in vitro. This phenomenon has been observed in bacteria as well as in higher organisms. In an effort to understand the impact of laboratory domestication on the foodborne pathogen Clostridium botulinum and related microbial food safety research, we investigated multiple spore stocks of C. botulinum Group II Beluga from our collection, as that is a widely applied model strain used in laboratories over decades. An acquired nutrient auxotrophy was confirmed as thymidine dependency using phenotypic microarrays. In parallel, whole-genome re-sequencing of all stocks revealed a mutation in thyA encoding thymidylate synthase essential for de-novo synthesis of dTMP from dUMP in the auxotrophic stocks. A thyA-deficient Beluga variant stock was successfully complemented by introducing an intact variant of thyA and thymidine prototrophy was restored, indicating that the thymidine auxotrophy was solely due to the presence of a SNP in thyA. Our data suggested that this mutation, deleterious under nutrient-poor growth conditions in a chemically defined medium, has been present and maintained in laboratory stocks for nearly 30 years. Yet, the mutation remained unidentified since receiving the strain, most likely due to routine use of culture conditions optimized for growth performance. This work pinpoints the need for careful monitoring of model strains extensively used in laboratory settings at both phenotypic and genomic level. In applications like food safety challenge tests, compromised strains could cause incorrect predictions and thereby have deleterious consequences. To mitigate the risk of acquiring mutations, we recommend keeping passage numbers of laboratory strains low and to avoid single-colony passaging. In addition, relevant strains should be subjected to regular WGS checks and physiological validation to exclude DNA mutations with potential negative impacts on research data integrity and reproducibility.

Improved inference of population histories by integrating genomic and epigenomic data.

With the availability of high-quality full genome polymorphism (SNPs) data, it becomes feasible to study the past demographic and selective history of populations in exquisite detail. However, such inferences still suffer from a lack of statistical resolution for recent, for example bottlenecks, events, and/or for populations with small nucleotide diversity. Additional heritable (epi)genetic markers, such as indels, transposable elements, microsatellites, or cytosine methylation, may provide further, yet untapped, information on the recent past population history. We extend the Sequential Markovian Coalescent (SMC) framework to jointly use SNPs and other hyper-mutable markers. We are able to (1) improve the accuracy of demographic inference in recent times, (2) uncover past demographic events hidden to SNP-based inference methods, and (3) infer the hyper-mutable marker mutation rates under a finite site model. As a proof of principle, we focus on demographic inference in Arabidopsis thaliana using DNA methylation diversity data from 10 European natural accessions. We demonstrate that segregating single methylated polymorphisms (SMPs) satisfy the modeling assumptions of the SMC framework, while differentially methylated regions (DMRs) are not suitable as their length exceeds that of the genomic distance between two recombination events. Combining SNPs and SMPs while accounting for site- and region-level epimutation processes, we provide new estimates of the glacial age bottleneck and post-glacial population expansion of the European A. thaliana population. Our SMC framework readily accounts for a wide range of heritable genomic markers, thus paving the way for next-generation inference of evolutionary history by combining information from several genetic and epigenetic markers.

Network medicine-based epistasis detection in complex diseases: ready for quantum computing.

Most heritable diseases are polygenic. To comprehend the underlying genetic architecture, it is crucial to discover the clinically relevant epistatic interactions (EIs) between genomic single nucleotide polymorphisms (SNPs)(1-3). Existing statistical computational methods for EI detection are mostly limited to pairs of SNPs due to the combinatorial explosion of higher-order EIs. With NeEDL (network-based epistasis detection via local search), we leverage network medicine to inform the selection of EIs that are an order of magnitude more statistically significant compared to existing tools and consist, on average, of five SNPs. We further show that this computationally demanding task can be substantially accelerated once quantum computing hardware becomes available. We apply NeEDL to eight different diseases and discover genes (affected by EIs of SNPs) that are partly known to affect the disease, additionally, these results are reproducible across independent cohorts. EIs for these eight diseases can be interactively explored in the Epistasis Disease Atlas (https://epistasis-disease-atlas.com). In summary, NeEDL demonstrates the potential of seamlessly integrated quantum computing techniques to accelerate biomedical research. Our network medicine approach detects higher-order EIs with unprecedented statistical and biological evidence, yielding unique insights into polygenic diseases and providing a basis for the development of improved risk scores and combination therapies.

Inference of host-pathogen interaction matrices from genome-wide polymorphism data.

Host-pathogen coevolution is defined as the reciprocal evolutionary changes in both species due to genotype x genotype (GxG) interactions at the genetic level determining the outcome and severity of infection. While co-analyses of host and pathogen genomes (co-GWAs) allow us to pinpoint the interacting genes, these do not reveal which host genotype(s) is/are resistant to which pathogen genotype(s). The knowledge of this so-called infection matrix is important for agriculture and medicine. Building on established theories of host-pathogen interactions, we here derive four novel indices capturing the characteristics of the infection matrix. These indices can be computed from full genome polymorphism data of randomly sampled uninfected hosts, as well as infected hosts and their pathogen strains. We use these indices in an Approximate Bayesian Computation method to pinpoint loci with relevant GxG interactions and to infer their underlying interaction matrix. In a combined SNP data set of 451 European humans and their infecting Hepatitis C Virus (HCV) strains and 503 uninfected individuals, we reveal a new human candidate gene for resistance to HCV and new virus mutations matching human genes. For two groups of significant human-HCV (GxG) associations, we infer a gene-for-gene infection matrix, which is commonly assumed to be typical of plant-pathogen interactions. Our model-based inference framework bridges theoretical models of GxG interactions with host and pathogen genomic data. It, therefore, paves the way for understanding the evolution of key GxG interactions underpinning HCV adaptation to the European human population after a recent expansion.

Genetic diversity, population structure, and phylogenetic relationships of a widespread East Asia herb, Cryptotaenia japonica Hassk. (Apiaceae) based on genomic SNP data generated by dd-RAD sequencing.

Single-nucleotide polymorphisms (SNPs) represent the most prevalent form of genomic polymorphism and are extensively used in population genetics research. Using dd-RAD sequencing, a high-throughput sequencing method, we investigated the genome-level diversity, population structure, and phylogenetic relationships among three morphological forms of the widely distributed taxon Cryptotaenia japonica Hassk., which is native to East Asia. Our study aimed to assess the species status of C. japonica according to its genetic structure and genetic diversity patterns among 66 naturally distributed populations, comprising 26C. japonica f. japonica, 36C. japonica f. dissecta (Y. Yabe) Hara and 4C. japonica f. pinnatisecta S. L. Liou accessions. Based on genomic SNP data generated by dd-RAD sequencing, we conducted genetic diversity, principal component, neighbor-joining (NJ) phylogenetic, admixture clustering, and population differentiation analyses. The findings revealed the following: (1) 5,39,946 unlinked, high-quality SNPs, with mean π, H O, H E and F IS values of 0.062, 0.066, 0.043 and -0.014, respectively, were generated; (2) population divergence was unaffected by isolation through distance; (3) six main distinct regions corresponding to geographic locations and exhibiting various levels of genetic diversity were identified; (4) pairwise F ST analysis showed significant (P < 0.05) population differentiation in 0%-14% of populations among the six regions after sequential Bonferroni correction; and (5) three migration events (historical gene flow) indicated east‒west directionality. Moreover, contemporary gene flow analysis using Jost's D, Nei's G ST, and Nm values highlighted the middle latitude area of East Asia as a significant contributor to genetic structuring in C. japonica. Overall, our study elucidates the relatively low genetic differentiation and population structure of C. japonica across East Asia, further enhancing our understanding of plant lineage diversification in the Sino-Japanese Floristic Region.

HPV16 Genomes: In Silico Analysis of E6 and E7 Oncoproteins in 20 South American Variants.

Human papillomavirus (HPV) is the main risk factor for the development of squamous cell cervical cancer, and E6 oncoprotein and E7 oncoprotein are important components of the viral genome and its oncogenic potential. It is known that different viral variants of HPV16 have different pathology and impact on the development of neoplasia, although few studies have been performed on South American variants. Therefore, the present study aimed to analyze in silico the genomic diversity of HPV16 in 20 complete genome variants of South America in the National Center for Biotechnology Information (NCBI) database. We performed a descriptive study to characterize the polymorphic regions of the E6 and E7 genes in HPV16 variants, using software for genomic data and single nucleotide polymorphism (SNP) analysis and others for phylogenetic analysis. The variants analyzed included six SNPs linked to cancer (A131G, G145T, C335T, T350G, C712A, and T732C) and significant variation (798 nucleotide substitutions). Despite this, the variants showed low genetic diversity. Eighteen variants of unclear significance (VUS) were identified, 10 of which were in the coding E6 regions and 8 in the coding E7 regions. The prevalence of lineage D variants is of concern due to their pathology in cervical cancer and requires more research and epidemiological vigilance regarding their prevalence in the population. The data obtained in this study may contribute to future research on South American variants of HPV16, their pathogenicity, and the development of treatments.

Comparative transcriptomics identifies genes underlying growth performance of the Pacific black-lipped pearl oyster Pinctada margaritifera

BackgroundIn bivalves, the rate at which organisms grow is a major functional trait underlying many aspects of their commercial production. Growth is a highly polygenic trait, which is typically regulated by many genes with small to moderate effects. Due to its complexity, growth variability in such shellfish remains poorly understood. In this study, we aimed to investigate differential gene expression among spat of the pearl oyster Pinctada margaritifera with distinct growth phenotypes.ResultsWe selected two groups of P. margaritifera spat belonging to the same F2 cohort based on their growth performance at 5.5 months old. Transcriptome profile analysis identified a total of 394 differentially expressed genes between these Fast-growing (F) and Slow-growing (S) phenotypes. According to functional enrichment analysis, S oysters overexpressed genes associated with stress-pathways and regulation of innate immune responses. In contrast, F oysters up-regulated genes associated with cytoskeleton activity, cell proliferation, and apoptosis. Analysis of genome polymorphism identified 16 single nucleotide polymorphisms (SNPs) significantly associated with the growth phenotypes. SNP effect categorization revealed one SNP identified for high effect and annotated for a stop codon gained mutation. Interestingly, this SNP is located within a gene annotated for scavenger receptor class F member 1 (SRF1), which is known to modulate apoptosis. Our analyses also revealed that all F oysters showed up-regulation for this gene and were homozygous for the stop-codon mutation. Conversely, S oysters had a heterozygous genotype and a reduced expression of this gene.ConclusionsAltogether, our findings suggest that differences in growth among the same oyster cohort may be explained by contrasted metabolic allocation between regulatory pathways for growth and the immune system. This study provides a valuable contribution towards our understanding of the molecular components associated with growth performance in the pearl oyster P. margaritifera and bivalves in general.

Genetic polymorphism in waxweed (Red Book of the Russian Federation) in North-West Russia

BACKGROUND: Waxweed (Myrica gale L.) is a protected plant species found in the Russian Federation only in the Leningrad Region and Karelia. It is almost not studied from the genetic point of view. This species is presumably hexaploid; it propagates mainly vegetatively, and the role of sexual reproduction in the life cycle of waxweed is unclear. All waxweed populations in the Russian Federation are small and belong to the edge ones (occupy the easternmost positions in the range). AIM: The aim of the study is to investigate genomic DNA polymorphism in waxweed populations in the Russian Federation, and to evaluate the role of sexual reproduction in propagation and dispersal of this species. MATERIALS AND METHODS: AFLP-analysis of waxweed genomic DNA in 6 natural populations (5 populations in the Leningrad Region, 1 in Karelia). Using 3 pairs of primers, we studied waxweed genomic polymorphism for 22 DNA fragments. RESULTS: Each of the studied waxweed populations is genetically polymorphic. Among 182 analyzed plants we distinguished 27 different AFLP-genotypes, two of which were common in all populations studied. Most of others AFLP genotypes (20) were represented just by a single plant or a couple of plants. Some of these rare AFLP genotypes are likely the results of mutation and/or recombination processes affecting the common AFLP genotypes. CONCLUSIONS: The role of sexual reproduction in waxweed propagation, although minor, is noticeable.

Population structure and genetic diversity of mango (Mangifera indica L.) germplasm resources as revealed by single-nucleotide polymorphism markers.

Mango is a vital horticultural fruit crop, and breeding is an essential strategy to enhance ongoing sustainability. Knowledge regarding population structure and genetic diversity in mango germplasm is essential for crop improvement. A set of 284 mango accessions from different regions of the world were subjected to high-throughput sequencing and specific-locus amplified fragment (SLAF) library construction to generate genomic single-nucleotide polymorphism (SNP). After filtering, raw data containing 539.61 M reads were obtained. A total of 505,300 SLAFs were detected, of which, 205,299 were polymorphic. Finally, 29,136 SNPs were employed to dissect the population structure, genetic relationships, and genetic diversity. The 284 mango accessions were divided into two major groups: one group consisted mainly of mango accessions from Australia, the United States, Cuba, India, Caribbean, Israel, Pakistan, Guinea, Burma, China, and Sri Lanka, which belonged to the Indian type (P1); the other group contained mango accessions from the Philippines, Thailand, Indonesia, Vietnam, Cambodia, Malaysia, and Singapore, which belonged to Southeast Asian type (P2). Genetic diversity, principal component analysis (PCA), and population structure analyses revealed distinct accession clusters. Current results indicated that the proposed hybridization occurred widely between P1 and P2. Most of the accessions (80.99%) were of mixed ancestry, perhaps including multiple hybridization events and regional selection, which merits further investigation.

The impact of comparative genomic hybridization/single-nucleotide polymorphism microarray in risk stratification of pediatric acute lymphoblastic leukemia.

The objective of this study is to assess the concordance and added value of combined comparative genomic hybridization plus single-nucleotide polymorphism microarray (CGH/SNP) analyses in pediatric acute lymphoblastic leukemia (ALL) risk stratification compared to conventional cytogenetic methods. This is a retrospective study that included patients aged 1-18years diagnosed with de novo ALL at Sainte-Justine Hospital between 2016 and 2021. Results from conventional cytogenetic and molecular analyses were collected and compared to those of CGH/SNP. A total of 135 ALL patients were included. Sample failures or non-diagnostic analyses occurred in 17.8% cases with G-banding karyotypes versus 1.5% cases with CGH/SNP. The mean turnaround time for results was significantly faster for CGH/SNP than karyotype with 5.8 versus 10.7days, respectively. The comparison of ploidy assessment by CGH/SNP and G-banding karyotype showed strong concordance (r=.82, p<.001, r2=.68). Furthermore, G-banding karyotype did not detect additional clinically relevant aberrations that were missed by the combined analysis of CGH/SNP and fluorescence in situ hybridization. The most common gene alterations detected by CGH/SNP were deletions involving CDKN2A (35.8%), ETV6 (31.3%), CDKN2B (28.4%), PAX5 (20.1%), IKZF1 (12.7%), and copy-neutral loss of heterozygosity (CN-LOH) of 9p (9.0%). Among these, only ETV6 deletion was found to have a significant prognostic impact with superior event-free survival in both univariate and multivariate analyses (adjusted hazard ratio 0.08, 95% confidence interval: 0.01-0.50, p=.02). CGH/SNP provided faster, reliable, and highly concordant results than those obtained by conventional cytogenetics. CGH/SNP identified recurrent gene deletions in pediatric ALL, of which ETV6 deletion conferred a favorable prognosis.

Genome-wide association study identifies host genetic variants influencing oral microbiota diversity and metabolic health

The microbial communities of the oral cavity are important elements of oral and systemic health. With emerging evidence highlighting the heritability of oral bacterial microbiota, this study aimed to identify host genome variants that influence oral microbial traits. Using data from 16S rRNA gene amplicon sequencing, we performed genome-wide association studies with univariate and multivariate traits of the salivary microbiota from 610 unrelated adults from the Danish ADDITION-PRO cohort. We identified six single nucleotide polymorphisms (SNPs) in human genomes that showed associations with abundance of bacterial taxa at different taxonomical tiers (P < 5 × 10–8). Notably, SNP rs17793860 surpassed our study-wide significance threshold (P < 1.19 × 10–9). Additionally, rs4530093 was linked to bacterial beta diversity (P < 5 × 10–8). Out of these seven SNPs identified, six exerted effects on metabolic traits, including glycated hemoglobin A1c, triglyceride and high-density lipoprotein cholesterol levels, the risk of type 2 diabetes and stroke. Our findings highlight the impact of specific host SNPs on the composition and diversity of the oral bacterial community. Importantly, our results indicate an intricate interplay between host genetics, the oral microbiota, and metabolic health. We emphasize the need for integrative approaches considering genetic, microbial, and metabolic factors.