Search Results (1,423)

Background: The health and viability of captive elephants, which are central to off-site conservation efforts and health management in Thailand, is threatened by emerging infectious diseases. This is partly due to genetic differences in immune-related genes, especially in the major histocompatibility complex (MHC) and, among these, loci such as DQA play a crucial role in immune surveillance. Data pertaining to MHC polymorphisms in elephants are scarce, and thus this study investigated such polymorphisms and selection signatures in a partial fragment of exon 2 of the MHC Class II DQA gene. Methods: The approach we used targeted next-generation sequencing and diversity analyses of individuals from three captive elephant camps in Northern Thailand. Results: Eight alleles containing 11 SNPs were identified in the exon 2 fragment, encompassing both silent and missense mutations, some of which may influence immune function. Notably, the allele Elma-DQA*TH3, which is identical to Loaf-DQA*01 and Elma-DQA*01, previously reported as the most common alleles in Loxodonta and Elephas, was found at low frequencies. This shift may reflect local selective pressures that shape MHC allele distributions. Evidence of mixed selection (both positive and balancing) was detected in the partial fragment of DQA exon 2, suggesting a dynamic interplay between evolutionary forces. Positive selection likely reflects an adaptation to emerging or locally prevalent pathogens, whereas balancing selection maintains allelic diversity over time to enable a broad immunological response. Conclusions: Our findings reveal immunogenetic variations in captive Thai elephants, and provides insights into host–pathogen interactions that inform conservation and health strategies with the aim of improving disease resilience. Full article

Local livestock genetic resources are crucial for sustainable agriculture and biodiversity conservation. Dengchuan cattle, a nationally protected dairy breed in China, are esteemed for their high milk fat content and cultural significance. However, they have been threatened by crossbreeding with exotic high-yielding breeds, resulting in a decline in purebred resources. In this study, we evaluated the genetic diversity and structure of a conserved population using 100K SNP microarray data from 74 individuals. After implementing strict quality control measures, 78,460 loci were retained for principal component analysis (PCA), which identified 100 SNPs most associated with PC1. After calculating high-consistency loci using PLINK, based on allelic consistency, we selected 61 high-stability markers to represent 60 individuals for further analysis. Genetic diversity parameters indicated moderate polymorphism, with an effective population size (Ne) of 2.293, observed heterozygosity (Ho) of 0.300, expected heterozygosity (He) of 0.326, and an average polymorphic information content (PIC) of 0.261. A paired t-test confirmed a highly significant difference between Ho and He (p < 0.001). Runs of homozygosity (ROH) revealed a moderate level of inbreeding (F_ROH = 0.0928), with bulls exhibiting slightly higher values than females. Neighbor-joining (NJ) clustering further indicated clear lineage distinctions among bulls, but lower kinship among females. Overall, Dengchuan cattle exhibit moderate genetic diversity but face risks due to a small Ne and an unbalanced family structure. Targeted breeding strategies and genetic monitoring are recommended to ensure sustainable conservation and utilization. Full article

Mutations may cause changes in the structure and function of immune-related proteins, thereby affecting the operation of the immune system. Deep mutational scanning combines saturation mutagenesis, functional selection, and high-throughput sequencing to evaluate the effects of mutations on a large scale and with high resolution. By systematically and comprehensively analyzing the impact of mutations on the functions of immune-related proteins, the immune response mechanism can be better understood. However, each stage in deep mutation scanning has its limits, and the approach remains constrained in several ways. These include data and selection biases that affect the robustness of effect estimates, insufficient library coverage and editability leading to uneven representation of sites and alleles, system-induced biased signals that deviate phenotypes from their true physiological state, and imperfect models and statistical processing that limit extrapolation capabilities. Therefore, this technology still needs further development. Herein, we summarize the principles and methods of deep mutational scanning and discuss its application in immunological research. The aim is to provide insights into the broader application prospects of deep mutational scanning technology in immunology. Full article

Leaf rust, a devastating fungal disease caused by Puccinia triticina (Pt), severely impacts wheat quality and yield. Identifying genetic loci for wheat leaf rust resistance, developing molecular markers, and breeding resistant varieties is the most environmentally friendly and economical strategy for disease control. This study utilized a recombinant inbred line (RIL) population of Doumai and Shi4185, combined with the wheat 90 K single nucleotide polymorphisms (SNPs) chip data and maximum disease severity (MDS) of leaf rust from four environments, to identify adult plant resistance (APR) loci through linkage mapping. Additionally, kompetitive allele-specific PCR (KASP) markers suitable for breeding were developed, and genetic effects were validated in a natural population. In this study, 5 quantitative trait loci (QTL) on chromosomes 1B (2), 2A and 7B (2) were identified through inclusive composite interval mapping, and named as QLr.lfnu-1BL1, QLr.lfnu-1BL2, QLr.lfnu-2AL, QLr.lfnu-7BL1 and QLr.lfnu-7BL2, respectively, explaining 4.54–8.91% of the phenotypic variances. The resistance alleles of QLr.lfnu-1BL1 and QLr.lfnu-1BL2 originated from Doumai, while the resistance alleles of QLr.lfnu-2AL, QLr.lfnu-7BL1 and QLr.lfnu-7BL2 came from Shi4185. Among these, QLr.lfnu-1BL2, QLr.lfnu-7BL1 and QLr.lfnu-7BL2 overlapped with previously reported loci, whereas QLr.lfnu-1BL1 and QLr.lfnu-2AL are likely to be novel. Two KASP markers, QLr.lfnu-2AL and QLr.lfnu-7BL, were significantly associated with leaf rust resistance in a diverse panel of 150 wheat varieties mainly from China. Totally, 34 potential candidate genes encoded the NLR proteins, receptor-like kinases, signaling kinases and transcription factors were selected as candidate genes for the resistance loci. These findings will provide stable QTL, available breeding KASP markers and candidate genes, and will accelerate the progresses of wheat leaf rust resistance improvement through marker-assisted selection breeding. Full article

Chewing cane is primarily consumed as fresh fruit and contains a variety of essential amino acids and iron. The identification and evaluation of chewing cane germplasm resources are prerequisites for the rational utilization of these resources, and phenotypic traits provide a direct and convenient means to determine breeding objectives. To facilitate the utilization and development of chewing cane germplasm, thirty-six phenotypic traits in 70 chewing cane germplasm resources were analyzed. The results revealed rich genetic diversity among the chewing cane resources. Seven phenotypic traits exhibited relatively high diversity and considerable potential for genetic improvement. The three groups exhibited relatively small genetic distances and relatively high genetic similarity coefficients, among which the Local varieties (Lv) group displayed the highest genetic diversity indices and retained more private alleles. Based on genetic similarity, the resources were classified into 3 groups, 5 subgroups, and 5 subclasses through cluster analysis, with more than half (54%) of the chewing cane materials forming a separate cluster. A total of 26 private alleles associated with 13 different phenotypic traits in chewing cane were identified across the three groups. The results of genetic diversity analysis based on phenotypic data provide important references for the utilization of chewing cane germplasm resources, selection of parents, and variety breeding. Full article

Background: Genetic improvement in wheat yield is the most focused research area for the breeding community to ensure sustainable production. Wheat kernel traits and biomass are considered key contributors to enhance crop yield. Methods: This study was designed to explore the genetic diversity of kernel and biomass traits in popular wheat varieties from the US Southern Great Plains using 264 doubled haploid (DH) lines mainly derived from TAM 114 or TAM 204. This population was evaluated in two field environments planted in alpha lattice design during the 2020 crop season. Kernel traits were collected using the hp Scanjet G4010 photo scanner for image capturing and GrainScan v3. software for image analysis. Biomass parameters were collected and processed manually. For genotyping genomic libraries were prepared and sequenced on Illumina NovaSeq 6000 to generate paired end reads of 150 bp. Sequences were aligned to the IWGSC RefSeq genome assembly v2.1 using the Burrows Wheeler Aligner for SNP calling. Results: A total of 59,482 polymorphic SNP markers were retained for genetic analysis after the filtration at 50% missing data and 5% minor allele frequency. To investigate the marker–trait association and the genomic regions, four genome-wide association study models were implemented using the R package GAPIT version 3.5. Based on the Bonferroni correction <8.41 × 10⁻⁷ was used as a threshold to declare marker-trait associations (MTAs) significant. The BLINK model identified 12 MTAs on chromosomes 1A, 2A, 2B, 4A, 4B, and 6B. Conclusions: The identified MTAs can be used to develop diagnostic markers for efficient selection and utilization in recombination breeding and cultivar development process. Full article

Strawberry (Fragaria × ananassa Duch.) is a widely cultivated and economically important fruit crop with increasing consumer demand worldwide. Nowadays, in Uzbekistan, strawberry cultivation surpasses that of many other fruits and vegetables in terms of production volume. However, most genetic studies have focused on a limited set of cultivars, leaving a substantial portion of varietal diversity unexplored. This study aimed to evaluate the genetic variability and heritability among selected strawberry cultivars, as well as correlations between certain valuable agronomic traits, using molecular and statistical approaches. Polymorphism analysis was performed, using 67 gene-specific SSR markers, through PCR, and allele variations were observed in 46.3% of the markers analyzed. Among them, 31 markers displayed polymorphic bands, identifying fifty alleles, with one to four alleles per marker. Phylogenetic analysis was performed using MEGA 11 software, while statistical evaluations included AMOVA (GenAIEx), correlation (OriginPro), and descriptive statistics based on standard agronomic methods. Additionally, the degree of cross-compatibility and pollen viability among the cultivars were studied, and their significance for cultivar hybridization was analyzed. The highest fruit weight was observed in the Cinderella cultivar (26.2 g), and a moderate negative correlation (r = −0.688) was found between fruit number and fruit weight. These findings demonstrate the potential of molecular tools for assessing genetic diversity and provide valuable insights for breeding programs aimed at developing improved strawberry cultivars with desirable agronomic traits. Full article

Dioscorea polystachya (Chinese yam) is a crop valued for both medicinal and edible purposes, and exhibits rich genetic diversity. However, research into its germplasm resources remains understudied, and molecular breeding efforts lag behind. To bridge this gap, this study employed an integrated approach, combining the analysis of 23 phenotypic traits (17 qualitative and 6 quantitative) with genotyping using 19 polymorphic SSR markers. This combined strategy was applied to 53 accessions collected across 16 Chinese provinces to assess genetic diversity, population structure, and marker–trait associations. Phenotypic analysis revealed high diversity, with the Shannon diversity index (I) ranging from 0.09 to 1.15 for qualitative traits and from 1.45 to 1.79 for quantitative traits. Tuber traits exhibited the highest variability (with a CV up to 71.45%), indicating significant potential for yield improvement. Principal component analysis distilled phenotypic variation into eight principal components (accounting for 73.13% of the cumulative variance), and elite germplasm (e.g., DP24, DP52) was selected for breeding based on this analysis. Stepwise regression prioritized eight core evaluation traits (e.g., flowering rate, tuber length). SSR markers amplified 80 alleles (mean 4.211/locus), showing moderate genetic diversity (He = 0.529, PIC = 0.585). Population structure analysis divided accessions into two subpopulations, correlated with geographic origins: Group 1 (northern/southwestern China) and Group 2 (central/eastern China), reflecting adaptation to local climates and human selection. Association analysis identified 10 SSR loci significantly linked (p < 0.01) to key traits, including YM07_2 (flowering, R² = 13.94%), YM37_2 (leaf margin color, R² = 19.03%), and YM19_3 (leaf width, R² = 19.34%). This study establishes a comprehensive genetic framework for Chinese yam, offering molecular tools for marker-assisted breeding and strategies to conserve high-diversity germplasm, thereby enhancing the utilization of this orphan crop. Full article

Background: Physical conditioning is essential to meet the operational demands of military environments. However, high-intensity exercise provokes muscle microinjuries resulting in exercise-induced muscle damage. This condition is typically monitored using serum biomarkers such as creatine kinase (CK), myoglobin (MYO), and lactate dehydrogenase (LDH). Nevertheless, individual variability and genetic factors complicate the interpretation. In this context, the rs1815739 variant (ACTN3), the most common variant related to exercise phenotypes, hypothetically could interfere with the muscle physiological response. This study aimed to evaluate the kinetics of serum biomarkers during a high-intensity activity and their potential association with rs1815739 polymorphism. Materials and Methods: 32 male cadets were selected during the Army Paratrooper Course. Serum was obtained at six distinct moments while they performed regular course tests and recovery time. Borg scale was assessed in 2 moments (~11 and ~17). Results: Serum levels of CK, CK-MB, MYO, and LDH significantly increase after exercise, proportionally to Borg’s level, following the applicability of longitudinal studies to understand biomarker levels in response to exercise. R allele carriers (ACTN3) were only slightly associated with greater levels of MYO and CK, mainly in relative kinetic levels, and especially at moments of greater physical demand/recovery. Although the ACTN3 was slightly related to different biomarker levels in our investigation, the success or healthiness in military activities is multifactorial and does not depend only on interindividual variability or physical capacity. Conclusions: Monitoring biomarkers and multiple genomic regions can generate more efficient exercise-related phenotype interventions. Full article

Bacterial wilt, caused by Ralstonia solanacearum, is a major constraint to tomato production globally. To uncover resistance loci and develop efficient molecular tools for breeding, we conducted disease phenotyping over two growing seasons, which revealed consistent variation in resistance and moderate broad-sense heritability (H² = 0.22–0.28), suggesting a genetic basis. A genome-wide association study (GWAS) was performed on a diverse panel of 267 tomato accessions, evaluated against two R. solanacearum strains. A major resistance locus was identified on chromosome 12, with the strongest association observed at SNP S12_2992992, located within a gene encoding a leucine-rich repeat (LRR) receptor-like protein. Haplotype analysis indicated that the resistance-associated allele is relatively rare (~13.5%) in the population, underscoring its potential value in breeding programs. Functional validation in an F₂ population derived from a cross between the susceptible ‘Seedathip6’ and the resistant ‘Hawaii 7996’ confirmed that the TT genotype at S12_2992992 was significantly associated with enhanced resistance. A Kompetitive Allele Specific PCR (KASP) marker was developed for this SNP, facilitating cost-effective and high-throughput selection. Collectively, these findings establish S12_2992992 as a robust and functionally informative marker, offering a valuable tool for accelerating bacterial wilt resistance breeding in tomato through marker-assisted selection. Full article

Background: High-temperature stress is one of the major abiotic stresses limiting cotton production. Identifying genetic loci and genes for heat tolerance is crucial for breeding heat-tolerant varieties. Methods: Given the complexity of heat tolerance phenotypes in cotton, this study, which focused on resource materials, identified an A/C SNP mutation at position 5486185 on chromosome D06 within the heat tolerance interval through genome-wide association studies (GWAS) of natural Gossypium hirsutum populations. Results: A total of 308 resource materials were identified and evaluated for their heat tolerance phenotypes over two years of field research. Kompetitive allele-specific PCR (KASP) molecular markers were developed on the basis of the D06-5486185 SNP to characterize the heat tolerance phenotypes of these 308 resource materials. Genotyping for heat tolerance-related traits and agronomic traits was also performed. Materials with the C/C haplotype at position D06-5486185 presented increased heat tolerance (higher pollen viability (PV), leaf area (LA), chlorophyll (Chl) and number of bolls on the third fruit branch (FB3) and a lower number of dry buds (DBs) and drop rate (DR)) without negatively impacting key yield traits. This locus is located in the intergenic region of two adjacent bZIP transcription factor genes (GH_D06G0408 and GH_D06G0409). Expression analysis revealed that the expression levels of these two genes were significantly greater in heat-tolerant accessions (C/C type) than in sensitive accessions and that their expression levels were significantly correlated with multiple heat-tolerant phenotypes. Conclusions: In summary, this study developed a Kompetitive Allele Specific PCR (KASP) marker associated with heat tolerance in G. hirsutum and identified two key heat tolerance candidate genes. These results provide an efficient marker selection tool and important genetic resources for the molecular breeding of heat-tolerant G. hirsutum, laying an important foundation for further establishing a molecular marker-assisted breeding system for heat tolerance in G. hirsutum. Full article

Background: Recent hypotheses suggest that mutations associated with alpha1 antitrypsin (AAT) deficiency (AATD) may influence the clinical presentation and progression of cystic fibrosis (CF). This study employs a longitudinal design to determine the prevalence of AATD mutations and assess their impact on CF. Methods: The study Finding AAT Deficiency in Obstructive Lung Diseases: Cystic Fibrosis (FADO-CF) is a retrospective cohort study evaluating people with CF from November 2020 to February 2024. On the date of inclusion, serum levels of AAT were measured and a genotyping of 14 mutations associated with AATD was performed. Historical information, including data on exacerbations, microbiological sputum isolations, and lung function, was obtained from the medical records, aiming at a temporal lag of 10 years. Results: The sample consisted of 369 people with CF (40.9% pediatrics). Of these, 58 (15.7%) cases presented at least one AATD mutation. The AATD allelic combinations identified were PI*MS in 47 (12.7%) cases, PI*MZ in 5 (1.4%) cases, PI*SS in 3 (0.8%) cases, PI*SZ in 2 (0.5%) cases, and PI*M/P_lowell in 1 (0.3%) case. The optimal cutoff value for AAT levels to detect AATD-associated mutation carriers was 129 mg/dL in the overall cohort (sensitivity of 73.0%; specificity 69.2%) and 99.5 mg/dL when excluding PI*MS cases (sensitivity 98.0%; specificity 90.9%), highlighting the need for lower thresholds in clinically severe genotypes to improve case detection. The number of mild exacerbations during the follow-up appeared to be associated with AATD mutations. Conclusions: AATD mutations are prevalent in CF and may impact certain clinical outcomes. If systematic screening was to be planned, we recommend considering the proposed cut-off points to select the population for genetic studies. Full article

Background/Objectives: Studies have shown that higher polygenic risk scores (PRSs) for Alzheimer’s disease (AD) are associated with smaller volumes in temporal brain regions typically affected by this disease. These effects have also been found in cognitively unimpaired (CU) older adults. This study aimed to investigate the relationship between PRSs and brain volumes in specific areas associated with early AD. Methods: 342 participants were selected from the Alzheimer’s Disease Neuroimaging Initiative and stratified into three groups: 114 amyloid-positive atrophic (A+N+), 114 amyloid-negative non-atrophic (A−N−), and 114 amyloid-positive non-atrophic (A+N−) people. Linear regressions were performed within each group to investigate associations between PRSs and regional grey matter volumes. Analyses were also repeated after stratifying groups by APOE status and clinical diagnosis. Two sensitivity analyses were run to investigate the impact of APOE and amyloid status and concordance across biomarkers. Multiplicity was controlled for using the Benjamini–Hochberg false discovery rate (FDR) approach. Results: Negative associations were observed between PRSs and volumes of the left amygdala and hippocampus in A+N+, right hippocampus in A+N−, and right posterior cingulate cortex in A−N− participants. Associations were found especially in A−N− participants, both ε4 allele carriers and non-carriers, and mostly confirmed in sensitivity analyses. Associations emerged only in CU and AD participants, but not in people with MCI. None of these findings survived correction for FDR. Conclusions: These findings highlight the potential of PRSs as novel biological indicators for a deeper characterisation of AD-related neural alterations. Full article

The Fukushima nuclear accident in 2011 caused adverse phenotypic changes in wild organisms in radioactively polluted areas. However, few studies have investigated genetic changes after the accident. Here, we analyzed the nuclear DNA sequences of internal transcribed spacer 2 (ITS2) from the pale grass blue butterfly Zizeeria maha collected in 2011–2014 (n = 389). We detected 29 haplotypes, but the most frequent haplotype (H1) represented 86% of alleles examined. The haplotype H22 from Takahagi phylogenetically had the latest sequence, suggesting that it may be a novel mutant produced by the accident or just a minor existing haplotype. In Fukushima Prefecture, the H1 percentage oscillated; it peaked in Fall 2011 and decreased in Spring 2012 but peaked again in Fall 2012. Haplotype diversity and nucleotide diversity were low in Spring 2012 and Fall 2012 and then increased. The ratio of H1 to nonH1 was significantly different between the early and late periods of our field surveys. These results suggest that genetic diversity in Fukushima Prefecture initially decreased through a selection process in response to the Fukushima nuclear accident but was recovered by Fall 2014, probably due to immigrants and emerging mutants, which is consistent with previous morphological abnormality data. Full article

Yak husbandry on the Qinghai–Tibetan Plateau relies on genetically resilient sire lines, yet the paternal ancestry of the locally prominent Jiuzhi breed has never been quantified. To resolve this gap, a 690 bp fragment of the Y chromosomal SRY gene was sequenced in 117 males spanning Jiuzhi (n = 12) and five neighboring Qinghai breeds and compared with three single individual public records that represent Qinghai Plateau, Tianzhu White, and Wild yaks. Alignment, haplotype calling, diversity indices, F_ST differentiation, AMOVA, multidimensional scaling, and TCS network analysis were performed. Thirty-two haplotypes were recovered; Jiuzhi yaks possessed twelve, and six of them had private alleles. Mean A + T content was 53.8%. Haplotype diversity was highest in Qinghai Plateau, Tianzhu White and Wild yaks and lowest in Larima yaks, while Jiuzhi diversity resembled that of Huanhu. Pairwise F_ST values indicated negligible differentiation between Jiuzhi and either Qinghai Plateau or Yushu yaks (F_ST ≈ 0) but pronounced divergence from Tianzhu White and Wild yaks (F_ST ≈ 0.97–0.99). AMOVA attributed 90.7% of molecular variance to among-breed differences, and multidimensional scaling clustered Jiuzhi with Jinchuan, Yushu and Huanhu. Network topology resolved two patrilineal clades, confirming dual paternal origins for Jiuzhi yaks. These data provide the first quantitative baseline for sire selection and conservation of Jiuzhi yaks and highlight close affinities with adjacent plateau breeds. Limitations include the use of single individual public sequences for Qinghai Plateau, Tianzhu White and Wild yaks (employed solely as phylogenetic anchors) and reliance on a single Y-linked locus; broader sampling and multilocus approaches will refine within-breed estimates. Full article