Whole Genome Sequencing Research Articles

Antimicrobial Susceptibility of Toxin-Producing Corynebacterium diphtheriae and C. ulcerans in Belgium

Background/Objectives: Despite a significant reduction in diphtheria incidence and mortality due to vaccination, antitoxin therapy and antibiotic treatments, a concerning resurgence is occurring in Europe. Resistance to penicillins and macrolides is emerging, resulting in a growing challenge for diphtheria management. This retrospective study aims to evaluate and compare antibiotic susceptibilities of both toxigenic Corynebacterium diphtheriae and C. ulcerans. Methods: Susceptibilities were assessed using broth microdilution—the gold standard—disk diffusion and the gradient method, and analyzed on the basis of the EUCAST breakpoint tables for the interpretation of MICs and zone diameters. Antimicrobial resistance genes and mutations were detected by analyzing whole-genome sequences (WGS). Results: A small number of C. diphtheriae isolates were resistant to the first-choice antimicrobial classes, penicillins and macrolides, while higher resistance rates were observed for ciprofloxacin (29%), tetracycline (38%) and trimethoprim-sulfamethoxazole (SXT, 85%). A good correlation was found with resistance genes and mutations detected by WGS. C. ulcerans isolates were susceptible to all tested antibiotics, except clindamycin, to which this species is naturally resistant, and a few ciprofloxacin resistances not confirmed by WGS. Diffusion techniques were found to be acceptable alternatives, but false susceptible results were detected for ciprofloxacin and tetracycline by disk diffusion and ciprofloxacin and SXT by gradient diffusion. Conclusions: Penicillins and macrolides remain the first-choice antibiotics for the treatment of diphtheria. However, antimicrobial susceptibility testing is needed for all toxigenic C. diphtheriae and C. ulcerans isolates, as resistance is emerging. Antimicrobial susceptibility testing should not be limited to penicillins and macrolides, but be extended to other antibiotics. When WGS is performed for epidemiological purposes, resistance genes and mutations should be looked for.

Whole-Genome Sequencing and Phenotyping Reveal Specific Adaptations of Lachancea thermotolerans to the Winemaking Environment.

Adaptation to the environment plays an essential role in yeast evolution as a consequence of selective pressures. Lachancea thermotolerans, a yeast related to fermentation and one of the current trends in wine technology research, has undergone an anthropisation process, leading to a notable genomic and phenomic differentiation. Using whole-genome sequencing, of 145 L. thermotolerans strains, we identified six well-defined groups primarily delineated by their ecological origin and exhibiting high levels of genetic diversity. Anthropised strains showed lower genetic diversity due to the selective pressure imposed by the winemaking environment. Strong evidence of anthropisation and adaptation to the wine environment through modification of gene content was also found. Differences in genes involved in the assimilation of alternative carbon and nitrogen sources, such as the MAL31 and DAL5 genes, which confer greater fitness in the winemaking environment, were observed. Additionally, we found that phenotypic traits considered domestication hallmarks are present in anthropised strains. Among these, increased fitness in the presence of ethanol and sulphites, assimilation of non-fermentable carbon sources, and lower levels of residual fructose under fermentative conditions highlight. We hypothesise that lactic acid production in the Saccharomyces-Lachancea lineage is an anthropisation signature linked to winemaking, resulting from the loss of respiratory chain complex I and the evolutionary preference for fermentation over respiration, even in the presence of oxygen. Overall, the results of this work provide valuable insight into the anthropisation process in L. thermotolerans and demonstrate how fermentation environments give rise to similar adaptations in different yeast species.

Complete genome sequencing and probiotic characterization of promising lactic acid bacterial strains isolated from dairy products in Egyptian markets

Abstract Background Probiotics refer to live bacteria that, when administered in a sufficiently, exert a beneficial influence on human health. Due to the probiotics' beneficial health advantages, dietary supplements are expanding rapidly as a self-care interest worldwide. It may be beneficial to administer probiotic strains resistant to antibiotics concurrently with an antibiotic treatment. Our study investigates nineteen dairy products collected from Egyptian markets, isolated, identified and underwent a characterization for probiotic features under demanding circumstances as NaCl, acid and bile salt environments. The antibiotic sensitivity test was performed later to the antimicrobial assessment against widespread both negative and positive gram-stained bacteria infecting humans, along with the antiviral evaluation against (SARS-CoV-2), the virus that has disturbed the world recently. Results Out of nineteen investigated isolates, five potential probiotic isolates were examined for probiotic characteristics. Our tested samples were of dairy origin (yogurt, cottage-cheese and sour milk) in Egypt, were identified as Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Pediococcus acidilactici. These promising isolates had withstood stressful factors, such as NaCl, acid, bile salts, and the antimicrobial advance. The genomes were characterized for the physiology, safety, and efficacy of these isolates for probiotic qualities plus the presence of mobile genetic components and prophages that influence the genome's flexibility. They lack virulence factors and pathogenicity, rather than the lack of antibiotic resistance genes. Conclusion Three promising isolates underwent complete genome sequencing with high-throughput second generation technology followed by comprehensive bioinformatic analysis. The results showed that our isolates possess traits enabling resilience to antimicrobial effects and stress factors that might cause problems in the human gut. Several trustworthy genomic analysis methods were used to confirm and provide detailed illustrations of all traits. Genomic analyses confirmed the presence of stable genomes due to including mobile genetic components such as phages and CRISPR clusters, which validate their quality and safe usage for human health.

The complete genome sequences of Bacillus velezensis B26: a promising biocontrol agent and biofertilizer

Bacillus velezensis is a bacterium widely recognized for its biocontrol properties and ability to promote plant growth. This study presents the whole-genome sequence of B. velezensis B26, a newly identified strain isolated from chicken carcass soil in Udupi, India. The bacterium showed strong activity against fungal pathogens and exhibited diverse enzymatic activities. The whole-genome sequencing was executed using Illumina technologies. Assembly revealed that strain B26 possesses a genome of 3,946,698-bp with a G+C content of 46.3%. Genome annotation identified 3776 protein-coding genes, 1 rRNA gene, 50 tRNA genes, 5 ncRNA genes, and 59 pseudogenes. Functional analysis of the B. velezensis B26 genome revealed 216 genes involved in carbohydrate metabolism, 3 genes in potassium metabolism, 148 genes linked for cofactors, vitamins, prosthetic groups and pigments, 10 genes involved in phosphorus metabolism, 24 genes associated with iron acquisition and metabolism, 20 genes for nitrogen metabolism, 6 genes involved in sulfur metabolism, 6 genes in secondary metabolism, 12 genes associated with metabolism of aromatic compounds, 43 genes involved in stress response and 36 genes associated with virulence, disease and defence. The raw sequence data generated in this work have been deposited in the NCBI database and the genome sequence is available under the accession number JAYKOV000000000. These genomic data provide insight into the biocontrol ability and plant-growth promoting capabilities of B. velezensis B26.

The influence of elevation on genetic structure and variability in a wetland crucifer of the Rocky Mountains.

In mountain ecosystems, environmental conditions (e.g., temperature, ultraviolet radiation) covary with elevation, potentially limiting gene flow over steep gradients. We hypothesized that, (1) due to stark elevational differences in environmental factors, populations from dissimilar elevations (e.g., montane versus alpine) are more strongly differentiated than populations from similar elevations; (2) patterns of migration reflect downslope dispersal more than upslope dispersal; and (3) alpine populations at the cold edge show evidence of expansion, while montane populations at the warm edge have declined. DNA polymorphisms in whole-genome sequences were studied from 6-10 genotypes each in populations of Cardamine cordifolia found at three montane sites (ranging from 2200 to 2800 m a.s.l.) and three alpine sites (ranging from 3000 to 3500 m a.s.l.). Statistical analyses assessed patterns of population structure, genetic diversity, migration, and historical demography since the Pleistocene. Populations maintained very high levels of nucleotide diversity (π range: 0.062-0.071) and were weakly differentiated (pairwise FST = 0.027) on average. Migration among alpine populations was also inferred, with no directionality of migration across elevation bands. Demographic inference suggests that both montane and alpine populations have declined in size since the Pleistocene. Environmental differences across elevation represent diffuse barriers to gene flow. Recent polyploidy and clonal reproduction likely explain excess heterozygosity and high nucleotide diversity within populations. The genetic similarity of populations across elevation suggests highly connected refugia during the Pleistocene; such results may indicate that montane and alpine populations will respond similarly to changing environmental conditions associated with climate change.

Identification of Elizabethkingia species by MALDI-TOF MS proteotyping.

Elizabethkingia species are groups of emerging opportunistic bacterial pathogens with a high mortality rate, causing healthcare-associated outbreaks worldwide. Rapid identification of Elizabethkingia species is important becausethese species show intrinsically carbapenem resistance and there are few data for using appropriate antibiotics. Until now, only whole-genome sequencing could accurately identify the seven Elizabethkingia species. Therefore, establishing rapid and accurate identification methods for Elizabethkingia species in clinical laboratories is vital. In this study, we developed new methods for identifying Elizabethkingia species using four biomarker protein peaks-ribosomal L29, L30, S21, and the YtxH domain-containing proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) proteotyping. This study demonstrates the potential of routine MALDI-TOF MS -based laboratory examination for the early identification of Elizabethkingia species.

Complete genome sequences of three Pseudomonas aeruginosa phages of the genus Phikmvvirus.

We describe the genomes of three lytic Pseudomonas aeruginosa phages of the genus Phikmvvirus. The genomes of phages vB_Pae4841-AFR43, vB_Pae10145-KEN1, and vB_Pae9718-KEN10 consist of 43,426, 43,406, and 43,118 bp, with 62.4%, 62.3%, and 62.2% GC content, contain 63, 66, and 64 coding sequences, respectively, and no tRNA genes.

Complete genome sequence of the Staphylococcus aureus NCCP 11854 isolated from a food-poisoning patient in the Republic of Korea.

Staphylococcus aureus is the etiological agent of skin diseases and food poisoning. In this study, we report the complete genome sequence of S. aureus NCCP 11854, which was originally isolated from the pus of a food-poisoning patient in the Republic of Korea in 2009.

Sequencing of a Thermoanaerobacter kivui isolate from DSMZ stock: major differences with reference assembly.

Thermoanaerobacter kivui DSM 2030 is an industrially relevant microbe, whose genome has been available since 2014. As the stock obtained from DSMZ appeared to be multiclonal, we obtained a complete genome sequence by de novo assembly of an isolate from the DSMZ stock and reported differences to the initial assembly.

Potential of Streptomyces rochei 8ER183 for poly(lactic acid)-degrading enzyme production, biodegradative capability, and its whole-genome sequence characterization

Potential of Streptomyces rochei 8ER183 for poly(lactic acid)-degrading enzyme production, biodegradative capability, and its whole-genome sequence characterization

Whole genome sequencing in early onset advanced heart failure

The genetic contributions to early onset heart failure (HF) are incompletely understood. Genetic testing in advanced HF patients undergoing heart transplantation (HTx) may yield clinical benefits, but data is limited. We performed deep-coverage whole genome sequencing (WGS) in 102 Swedish HTx recipients. Gene lists were compiled through a systematic literature review. Variants were prioritized for pathogenicity and classified manually. We also compared polygenic HF risk scores to a population-based cohort. We found a pathogenic (LP/P) variant in 34 individuals (34%). Testing yield was highest in hypertrophic (63% LP/P carriers), dilated (40%) and arrhythmogenic right ventricular (33%) cardiomyopathy and lower in ischemic cardiomyopathy (10%). A family history was more common in LP/P variant carriers than in non-carriers but was present in less than half of carriers (44% vs 13%, P < 0.001), whereas age was similar. Polygenic risk scores were similar in HTx recipients and the population cohort. In conclusion, we observed a high prevalence of pathogenic cardiomyopathy gene variants in individuals with early-onset advanced HF, which could not accurately be ruled out by family history and age. In contrast, we did not observe higher polygenic risk scores in early onset advanced HF cases than in the general population.

Genomic characteristics of ST6115 carbapenem-resistant Klebsiella pneumoniae coharboring blaNDM-1 and blaIMP-4

ObjectivesThe aim of this study is to characterize the genomic features of ST6115 carbapenem-resistant Klebsiella pneumoniae (CRKP) co-harboring blaNDM-1 and blaIMP-4.MethodsThe genome sequences of one ST6115 Klebsiella pneumoniae (KP) strain and 12 ST17 KP strain were obtained through whole genome sequencing (WGS). Subsequently, a phylogenetic analysis was employed to ascertain the clonal relationship of these strains. The antimicrobial susceptibility testing (AST) was evaluated through the application of the minimum inhibitory concentration (MIC) methodology by the broth microdilution method. Annotation and analysis of the genome enabled the identification of the plasmid structure and the comparative analysis of the genetic background. Finally, the conjugation transfer experiment was conducted to assess the transferability of the plasmid pHD8428-NDM-IMP.ResultsA comparable phylogenetic analysis revealed that ST6115 HD8428 and the majority of ST17 strains (9/12) were clustered on the same clade, which suggests a close relationship between two ST types. Additionally, HD8428 showed particularly close genetic similarity to HD11490, with a single-nucleotide polymorphism (SNP) difference of only 273. The analysis of the antibiotic resistance genes carried by the 13 strains revealed that all strains carry extended-spectrum β-lactamase (ESBL) genes. AST revealed that HD8428 exhibited resistance to a diverse range of antibiotics. The blaNDM-1 and blaIMP-4 genes were identified as being located on the plasmid pHD8428-NDM-IMP. Further analysis demonstrated that the blaNDM-1 gene was present on ΔTn125, while the blaIMP-4 gene was located on In1377-2. The results of the conjugation experiment indicated that plasmid pHD8428-NDM-IMP may pose a risk for the transmission of antibiotic resistance in healthcare settings.ConclusionWe report a clinical ST6115 strain HD8428 and identify the coexistence of blaNDM-1 and blaIMP-4 in the IncHI5 type plasmid pHD8428-NDM-IMP. HD8428 was resistant to a wide range of antibiotics and harbored the transmissible plasmid pHD8428-NDM-IMP, which made it a potential threat to public health. Our study indicates that the healthcare system and services should remain vigilant regarding the spread and prevalence of ST6115.

Complete genome sequences of two verona integron-encoded metallo-ß-lactamase (VIM)-producing enterobacterales isolated from dogs in the United States.

This announcement reports the complete genome sequences, created by combined Illumina and Oxford Nanopore sequencing, of two carbapenemase-producing Enterobacterales (Escherichia coli [LaAc-1-20] and Enterobacter hormaechei, strain 19632-21) isolated from dogs in the United States. Both isolates harbor a blaVIM-4 gene found on a 47 kb plasmid and on the bacterial chromosome, respectively.

A cost-effective, high-throughput, highly accurate genotyping method for outbred populations.

Affordable sequencing and genotyping methods are essential for large-scale genome-wide association studies. While genotyping microarrays and reference panels for imputation are available for human subjects, nonhuman model systems often lack such options. Our lab previously demonstrated an efficient and cost-effective method to genotype heterogeneous stock rats using double-digest genotyping by sequencing. However, low-coverage whole-genome sequencing offers an alternative method that has several advantages. Here, we describe a cost-effective, high-throughput, high-accuracy genotyping method for N/NIH heterogeneous stock rats that can use a combination of sequencing data previously generated by double-digest genotyping by sequencing and more recently generated by low-coverage whole-genome sequencing data. Using double-digest genotyping-by-sequencing data from 5,745 heterogeneous stock rats (mean 0.21× coverage) and low-coverage whole-genome sequencing data from 8,760 heterogeneous stock rats (mean 0.27× coverage), we can impute 7.32 million biallelic single-nucleotide polymorphisms with a concordance rate > 99.76% compared to high-coverage (mean 33.26× coverage) whole-genome sequencing data for a subset of the same individuals. Our results demonstrate the feasibility of using sequencing data from double-digest genotyping by sequencing or low-coverage whole-genome sequencing for accurate genotyping and demonstrate techniques that may also be useful for other genetic studies in nonhuman subjects.

Molecular and Clinical Characterization of Invasive Streptococcus pyogenes Isolates: Insights from Two Northern-Italy Centers

Streptococcus pyogenes (Group A Streptococcus, GAS) is a Gram-positive pathogen responsible for both superficial and invasive infections (iGAS), with increasing global incidence in recent years. This study aims to characterize the molecular and clinical features of iGAS cases in Bologna and Imola (Italy) between 2022 and 2024. Thirty-five invasive isolates were analyzed through whole-genome sequencing (WGS) to investigate the distribution of emm types, antimicrobial resistance (AMR) genes, and virulence factors. Clinical and epidemiological data were retrospectively collected and analyzed. The majority of cases (80%) were recorded in 2023, predominantly among patients aged over 65 (60%). Bloodstream infections were present in 97.1% of cases, and comorbidities such as diabetes and immunosuppression were common. Empirical antibiotic therapy often involved penicillin/β-lactam inhibitors, while oxazolidinones were the most frequently used in targeted regimens. The in-hospital mortality rate was 20%. Genomic analysis identified emm1, emm12, and emm89 as the most prevalent types, associated with specific virulence profiles and resistance determinants. This study highlights the critical role of emm typing and genomic characterization in understanding the pathogenicity of GAS. These findings contribute to the identification of risk factors for severe outcomes and underscore the need for targeted prevention and treatment strategies in vulnerable populations.

The genetic landscape of early-onset Alzheimer's disease in China.

Research on somatic and germline mutations in Chinese individuals with early-onset Alzheimer's disease (EOAD) has been limited. We conducted whole-genome sequencing of blood DNA from 108 patients with EOAD and 116 controls. The analysis included somatic and germline mutations across coding and non-coding regions, mutational signature determination, pathway enrichment identification, and predictive model. The mutational burden was significantly higher in the EOAD group compared to the control group. The prevalence of single-base substitution signature 5, which is strongly associated with aging, was much higher in patients with EOAD than in controls. EOAD-specific somatic mutations were identified in genes such as MIR31HG, TUBB4B, and APP. Germline mutations in DOCK3, PCSK5, and PDE4D were significantly associated with age of dementia onset. Furthermore, a predictive model comprising 15 mutations demonstrated an area under the curve of 0.78. The accumulation of senescence-related somatic mutations may increase the risk of developing EOAD. Whole genome sequencing was used to find somatic and germline mutations in Chinese individuals with early-onset Alzheimer's disease (EOAD). Total number and burden of blood somatic mutations were significantly higher. The prevalence of single-base substitution signature 5 was notably elevated in EOAD. EOAD-specific somatic mutations were identified in MIR31HG, TUBB4B, and APP. DOCK3, PCSK5, and PDE4D germline mutations were associated with the age of EOAD onset.

Source attribution of human Campylobacter infection: a multi-country model in the European Union

IntroductionInfections caused by Campylobacter spp. represent a severe threat to public health worldwide. National action plans have included source attribution studies as a way to quantify the contribution of specific sources and understand the dynamic of transmission of foodborne pathogens like Salmonella and Campylobacter. Such information is crucial for implementing targeted intervention. The aim of this study was to predict the sources of human campylobacteriosis cases across multiple countries using available whole-genome sequencing (WGS) data and explore the impact of data availability and sample size distribution in a multi-country source attribution model.MethodsWe constructed a machine-learning model using k-mer frequency patterns as input data to predict human campylobacteriosis cases per source. We then constructed a multi-country model based on data from all countries. Results using different sampling strategies were compared to assess the impact of unbalanced datasets on the prediction of the cases.ResultsThe results showed that the variety of sources sampled and the quantity of samples from each source impacted the performance of the model. Most cases were attributed to broilers or cattle for the individual and multi-country models. The proportion of cases that could be attributed with 70% probability to a source decreased when using the down-sampled data set (535 vs. 273 of 2627 cases). The baseline model showed a higher sensitivity compared to the down-sampled model, where samples per source were more evenly distributed. The proportion of cases attributed to non-domestic source was higher but varied depending on the sampling strategy. Both models showed that most cases could be attributed to domestic sources in each country (baseline: 248/273 cases, 91%; down-sampled: 361/535 cases, 67%;).DiscussionThe sample sizes per source and the variety of sources included in the model influence the accuracy of the model and consequently the uncertainty of the predicted estimates. The attribution estimates for sources with a high number of samples available tend to be overestimated, whereas the estimates for source with only a few samples tend to be underestimated. Reccomendations for future sampling strategies include to aim for a more balanced sample distribution to improve the overall accuracy and utility of source attribution efforts.

De novo acquisition of antibiotic resistance in six species of bacteria.

Bacteria can become resistant to antibiotics in two ways: by acquiring resistance genes through horizontal gene transfer and by de novo development of resistance upon exposure to non-lethal concentrations. The importance of the second process, de novo build-up, has not been investigated systematically over a range of species and may be underestimated as a result. To investigate the DNA mutation patterns accompanying the de novo antibiotic resistance acquisition process, six bacterial species encountered in the food chain were exposed to step-wise increasing sublethal concentrations of six antibiotics to develop high levels of resistance. Phenotypic and mutational landscapes were constructed based on whole-genome sequencing at two time points of the evolutionary trajectory. In this study, we found that (1) all of the six strains can develop high levels of resistance against most antibiotics; (2) increased resistance is accompanied by different mutations for each bacterium-antibiotic combination; (3) the number of mutations varies widely, with Y. enterocolitica having by far the most; (4) in the case of fluoroquinolone resistance, a mutational pattern of gyrA combined with parC is conserved in five of six species; and (5) mutations in genes coding for efflux pumps are widely encountered in gram-negative species. The overall conclusion is that very similar phenotypic outcomes are instigated by very different genetic changes. The outcome of this study may assist policymakers when formulating practical strategies to prevent development of antimicrobial resistance in human and veterinary health care.IMPORTANCEMost studies on de novo development of antimicrobial resistance have been performed on Escherichia coli. To examine whether the conclusions of this research can be applied to more bacterial species, six species of veterinary importance were made resistant to six antibiotics, each of a different class. The rapid build-up of resistance observed in all six species upon exposure to non-lethal concentrations of antimicrobials indicates a similar ability to adjust to the presence of antibiotics. The large differences in the number of DNA mutations accompanying de novo resistance suggest that the mechanisms and pathways involved may differ. Hence, very similar phenotypes can be the result of various genotypes. The implications of the outcome are to be considered by policymakers in the area of veterinary and human healthcare.

Emergence of Multidrug-Resistant NDM-5-Producing ST307 Klebsiella pneumoniae in Uruguay, 2023.

Carbapenem and colistin-resistant Klebsiella pneumoniae pose a significant threat to public health, particularly in intensive care units, due to high morbidity and mortality rates. This study aimed to analyze five NDM carbapenemase-producing multidrug-resistant K. pneumoniae isolates from different hospitals. Antimicrobial susceptibility testing, hypermucoviscosity analysis, biofilm production assessment, MLST, PCR, and whole-genome sequencing were conducted. All isolates harbored NDM-5 metallo-β-lactamase, belonging to MLST 307, were biofilm producers and exhibited a stop codon (Q30) along MgrB. Genomic analysis revealed multiple-replicon plasmids carrying resistance genes, notably blaNDM-5, blaCTX-M-15, rmtB, and qnrB1, with complex genetic structures encoding several mobile genetic elements, including the Tn3 family and IS26. All isolates harbored wzi173 (capsule-locus KL102), iutA (a siderophore-associated gene), and the type 3 fimbriae mrkABCDFHIJ operon. The core genome single nucleotide polymorphisms (SNPs) analysis suggests the circulation of two strains of ST307 clone (SNPs range differences 4-77). These findings highlight the potential plasticity of the high-risk ST307 clone and the urgent need for surveillance and intervention strategies to combat antimicrobial resistance. To our knowledge, this is the first report of K. pneumoniae ST307 carrying blaNDM-5 and the first description of ST307 in Uruguay. The presence of blaNDM-5 and pan-aminoglycoside resistance rmtB genes are identified for the first time in Uruguay.

Genetic resonance: dissecting the heritability and genetic correlations of human hearing acuity.

This study presents a frequency-specific, pedigree-based assessment of hearing acuity heritability. We analysed 34 Utah Centre d'Etude du Polymorphisme Humain (CEPH) pedigrees comprising 464 individuals, using whole-genome sequencing (WGS) and audiometric evaluations. Our analysis reveals a general decline in narrow-sense heritability as frequency increases. When calculated using the Sequential Oligogenic Linkage Analysis Routines (SOLAR) software package, narrow-sense heritability estimates drop from 51% at 250 Hz to 30% at 8000 Hz. Genetic correlations (Rho(G)), the degree to which genetic variation in one trait correlates with another, are higher for hearing acuity at similar frequencies. For example, Rho(G) between 250 and 500 Hz is 0.80, and Rho(G) between 6000 and 8000 Hz is 0.91. In contrast, frequencies distant from each other exhibit decreased Rho(G) with a genetic correlation of only 0.21 for hearing acuity at frequencies 250 and 8000 Hz. This assessment of the genetics underlying hearing acuity in a family-based design provides new details of genetic factors influencing hearing acuity in a frequency-specific approach.