Differences In Allele Frequencies Research Articles

A Dominance Hypothesis Argument for Historical Genetic Gains and the Fixation of Heterosis in Octoploid Strawberry.

Heterosis was the catalyst for the domestication of cultivated strawberry (Fragaria × ananassa), an interspecific hybrid species that originated in the 1700s. The hybrid origin was discovered because the phenotypes of spontaneous hybrids transgressed those of their parent species. The transgressions included fruit yield increases and other genetic gains in the twentieth century that sparked the global expansion of strawberry production. The importance of heterosis to the agricultural success of the hybrid species, however, has remained a mystery. Here we show that heterosis has disappeared (become fixed) among improved hybrids within a population (the California population) that has been under long-term selection for increased fruit yield, weight, and firmness. We found that the highest yielding hybrids are among the most highly inbred (59-79%), which seems counterintuitive for a highly heterozygous, outbreeder carrying heavy genetic loads. Although faint remnants of heterosis were discovered, the between-parent allele frequency differences and dispersed favorable dominant alleles necessary for heterosis have decreased nearly genome-wide within the California population. Conversely, heterosis was prevalent and significant among wide hybrids, especially for fruit count, a significant driver of genetic gains for fruit yield. We attributed the disappearance (fixation) of heterosis within the California population to increased homozygosity of favorable dominant alleles and inbreeding associated with selection, random genetic drift, and selective sweeps. Despite historical inbreeding, the highest yielding hybrids reported to-date are estimated to be heterozygous for 20,370-44,280 of 97,000-108,000 genes in the octoploid genome, the equivalent of an entire diploid genome or more.

Genotype distribution and allele frequency of thioester-containing protein 1(Tep1) and its effect on development of Plasmodium oocyst in populations of Anopheles arabiensis in Ethiopia.

Thioester-containing protein 1 (TEP1) is a crucial component of mosquitoes' natural resistance to parasites. To effectively combat malaria, there is a need to better understand how TEP1 polymorphism affects phenotypic traits during infections. Therefore, the purpose of this study was to determine the Tep1 genotype frequency in malaria vector populations from south-western Ethiopia and investigate its effect on Plasmodium oocyst development in Anopheles arabiensis populations. Using standard dippers, Anopheles mosquito larvae were collected from aquatic habitats in Asendabo, Arjo Dedessa, and Gambella in 2019 and 2020. Collected larvae were reared to adults and identified morphologically. Female An. gambiae s.l. were allowed to feed on infected blood containing the same number of gametocytes obtained from P. falciparum and P. vivax gametocyte-positive individuals using indirect membrane feeding methods. Polymerase Chain Reaction (PCR) was used to identify An. gambiae s.l. sibling species. Three hundred thirty An. gambiae s.l. were genotyped using Restricted Fragment Length Polymorphism (RFLP) PCR and sub samples were sequenced to validate the TEP1 genotyping. Among the 330 samples genotyped, two TEP1 alleles, TEP1*S1 (82% frequency) and TEP1*R1 (18% frequency), were identified. Three equivalent genotypes, TEP1*S1/S1, TEP1*R1/R1, and TEP1*S1/R1, had mean frequencies of 65.15%, 2.12%, and 32.73%, respectively. The nucleotide diversity was ranging from 0.36554 to 0. 46751 while haplotype diversity ranged from 0.48871 to 0.63161, across all loci. All sample sites had positive Tajima's D and Fu's Fs values. There was a significant difference in the TEP1 allele frequency and genotype frequency among mosquito populations (p < 0.05), except populations of Anopheles arabiensis from Asendabo and Gambella (p > 0.05). In addition, mosquitoes with the TEP1 *RR genotype were susceptible and produced fewer Plasmodium oocysts than mosquitoes with the TEP1 *SR and TEP1 *SS genotypes. The alleles identified in populations of An. arabiensis were TEP1*R1 and TEP1*S1. There was no significant variation in TEP1*R1 allele frequency between the high and low transmission areas. Furthermore, An. arabiensis carrying the TEP1*R1 allele was susceptible to Plasmodium infection. Further studies on vector-parasite interactions, particularly on the TEP1 gene, are required for vector control techniques.

Heterogeneous genetic architectures of prostate cancer susceptibility in sub-Saharan Africa.

Men of African descent have the highest prostate cancer incidence and mortality rates, yet the genetic basis of prostate cancer in African men has been understudied. We used genomic data from 3,963 cases and 3,509 controls from Ghana, Nigeria, Senegal, South Africa and Uganda to infer ancestry-specific genetic architectures and fine-map disease associations. Fifteen independent associations at 8q24.21, 6q22.1 and 11q13.3 reached genome-wide significance, including four new associations. Intriguingly, multiple lead associations are private alleles, a pattern arising from recent mutations and the out-of-Africa bottleneck. These African-specific alleles contribute to haplotypes with odds ratios above 2.4. We found that the genetic architecture of prostate cancer differs across Africa, with effect size differences contributing more to this heterogeneity than allele frequency differences. Population genetic analyses reveal that African prostate cancer associations are largely governed by neutral evolution. Collectively, our findings emphasize the utility of conducting genetic studies that use diverse populations.

Cross-ancestry analysis of brain QTLs enhances interpretation of schizophrenia genome-wide association studies.

Research on brain expression quantitative trait loci (eQTLs) has illuminated the genetic underpinnings of schizophrenia (SCZ). Yet most of these studies have been centered on European populations, leading to a constrained understanding of population diversities and disease risks. To address this gap, we examined genotype and RNA-seq data from African Americans (AA, n= 158), Europeans (EUR, n= 408), and East Asians (EAS, n= 217). When comparing eQTLs between EUR and non-EUR populations, we observed concordant patterns of genetic regulatory effect, particularly in terms of the effect sizes of the eQTLs. However, 343,737 cis-eQTLs linked to 1,276 genes and 198,769 SNPs were found to be specific to non-EUR populations. Over 90% of observed population differences in eQTLs could be traced back to differences in allele frequency. Furthermore, 35% of these eQTLs were notably rare in the EUR population. Integrating brain eQTLs with SCZ signals from diverse populations, we observed a higher disease heritability enrichment of brain eQTLs in matched populations compared to mismatched ones. Prioritization analysis identified five risk genes (SFXN2, VPS37B, DENR, FTCDNL1, and NT5DC2) and three potential regulatory variants in known risk genes (CNNM2, MTRFR, and MPHOSPH9) that were missed in the EUR dataset. Our findings underscore that increasing genetic ancestral diversity is more efficient for power improvement than merely increasing the sample size within single-ancestry eQTLs datasets. Such a strategy will not only improve our understanding of the biological underpinnings of population structures but also pave the way for the identification of risk genes in SCZ.

Advancing pharmacogenomic research in US Hmong populations: prevalence of key single nucleotide variations in California Hmong.

In collaboration with the Minnesota Hmong community, we have previously discovered significant differences in allele frequencies for key Single Nucleotide Variations (SNVs) within Very Important Pharmacogenes (VIPs) between Hmong and East Asians. Recognizing the potential clinical implications of these observed differences, we sought to validate these observations in a Hmong cohort residing in California, the state with the largest Hmong population in the US. Robust validation of these differences would affect motivation for clinicians treating individuals who identify as Hmong to consider pharmacogenomic (PGx) testing as a means to improve clinical decision making when using therapeutic agents in this unique population. Guided by California Hmong community leaders and utilizing the basic approach of community-based participatory research, demographic, clinical information and a buccal swab was obtained from Hmong adults residing in California. A commercial PGx testing panel was performed on these samples and specific allele frequencies of interest were compared between California and Minnesota Hmong. Allele frequency differences between California Hmong, East Asians and Europeans, were also compared. Return-of-PGx-results and presentations of group data were made to members of the Hmong along with PGx educational sessions to help interpret the observations. In 118 California Hmong who completed the study, the allele frequencies for SNV's were similar to previous Minnesota Hmong results. Furthermore, out of the 18 SNVs that were not previously reported in Hmong, allele frequencies were statistically different in 38% (7/18) of SNVs comparing California Hmong to East Asians, and in 77.8% (14/18) SNVs comparing California Hmong to Europeans. These results validate the original study's findings that Hmong people living in different US locations have similar allele frequencies for key PGx genes. Further, for many of these PGx genes, their allele frequencies are significantly different compared to either East Asians or Europeans. Clinicians should consider these important differences when prescribing medications for people who identify as Hmong.

Abstract C051: Impact of population pharmacogenomics on cisplatin-induced neurotoxicities

Abstract Background: Studies have shown that taxane-treated breast cancer patients with African (AFR) ancestry experience worse peripheral sensory neuropathy (PSN), while African American vincristine-treated leukemia patients have less PSN than Europeans (EUR). We hypothesized that ancestral disparities may exist for cisplatin-induced neurotoxicities and may relate to differences in allele frequency and resultant gene expression of SNPs associated with these toxicities. Methods: In our Platinum Study of 1680 genotyped testicular cancer survivors (TCS), multidimensional scaling scores were anchored by the 1000 Genomes population to classify geographic ancestry. PSN (EORTC-CIPN20) and other toxicities plus clinical and lifestyle variables were examined for associations between geographic ancestry and phenotypes using logistic regression and Wilcoxon rank sum test. Genotyped SNPs with Fst &amp;gt; 0.25 in 1000 Genomes were identified and evaluated with GTEx data to find expression or splicing quantitative trait loci in nerve/brain tissue or for cisplatin-associated candidate genes, across all tissues. LDmatrix was used to find linkage disequilibrium. If a block of SNPs had R2 &amp;gt; 0.75, one independent SNP was kept for association analysis. Logistic regression with age at questionnaire completion and 10 genetic principal components as covariates was used to calculate the association between genotype and toxicity. Results: In an analysis of patients who received 400-450 mg/m2 of cisplatin including EUR (n=681), Asian (ASN) axis (n=44) and AFR (n=13), the odds ratio (OR) for any neuropathy vs. none in the AFR vs. EUR was 7.8 (P=0.049) and in the AFR vs. ASN axis (including East Asian 1000 Genomes populations) was 10.0 (P=0.034). TCS with AFR ancestry had significantly more vertigo. There were 19,874 SNPs for analysis from the genome-wide approach and 118 SNPs from the candidate gene approach. While associations between genotype and toxicity did not reach Bonferroni threshold, some SNPs had p-values in the 10-5 range. For PSN, one SNP had increased frequency of a risk allele in the AFR population while the other had increased frequency of a protective allele, while for vertigo, four SNPs had increased frequency of risk alleles in the AFR population. Of interest was rs34904346, in which the TT vs. AA genotype had an OR of 1.9 (p=2x10-5) for any vs. no PSN, with the T allele having 90% frequency in AFR ancestry patients versus ∼60% in other populations. This SNP and three other independent SNPs associated with PSN incidence (p∼10-3) are eQTLs for RNF24 in nerve tissue, which interacts with membrane proteins that regulate intracellular calcium levels. Conclusions: We show preliminary evidence for the role of differing risk allele frequencies across populations in explaining disparities in cisplatin-induced PSN and vertigo, likely in combination with structural and environmental factors. Genotyping risk alleles could customize dosing, treatment, and post-treatment monitoring to benefit all cisplatin-treated patients. Citation Format: Swetha Nakshatri, Paul C. Dinh, Darren R. Feldman, Robert J. Hamilton, Chunkit Fung, David J. Vaughn, Christian Kollmannsberger, Robert Huddart, Lawrence H. Einhorn, Nancy J. Cox, Lois B. Travis, Eileen Dolan. Impact of population pharmacogenomics on cisplatin-induced neurotoxicities [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C051.

Ancestry-Related Differences in Allele and Genotype Frequencies of EGF A61G Polymorphism in the Cuban Population

Background: The polymorphism rs4444903 of the Epidermal Growth Factor gene (EGF A61G) causes differences in the EGF serum levels. It has become a biomarker for genetic susceptibility to cancer and a pharmacogenomic marker for therapies involving the EGF/EGF-receptor pathway. Objective: The present study aimed to characterize the allele and genotype frequencies of the rs4444903 in a Cuban sample and its relationship to a specific genetic ancestry. Methods: A cross-sectional study was carried out. Genomic data was collected from a dense genome-wide genotyping array analysis of 948 Cubans from all provinces. The allele and genotype frequencies of the rs4444903 were calculated. Analysis of ancestryrelated allelic/genotypic differences was performed. Results: The frequencies for both alleles were found to be very similar (0.52 for G vs. 0.48 for A allele), and genotype frequencies were 24.3%, 47.9%, and 27.8% for AA, AG, and GG, respectively. Greater differences were found between Cuban provinces, with frequencies for the G allele ranging from 0.38 in Artemisa to 0.69 in Guantánamo and for the GG genotype from 14.29% in Mayabeque to 50.88% in Guantánamo. An increased African-ancestry proportion was related to a higher probability of carrying G allele and GG genotype, with a significant (p=0.0038, q=0.024) African-ancestry-enrichment pattern. Conclusion: African ancestry seems to contribute to an increase in the EGF61*G allele in Cubans. Geographic patterns in admixture proportions for African and European ancestry are a determinant factor in the allelic and genotypic frequency differences between Cuban provinces. Such differences should be observed when designing association studies and implementing therapeutic approaches based on the EGF/EGF receptor pathway in Cuba.

Does HLA explain the high incidence of childhood-onset type 1 diabetes in the Canary Islands? The role of Asp57 DQB1 molecules

The Canary Islands inhabitants, a recently admixed population with significant North African genetic influence, has the highest incidence of childhood-onset type 1 diabetes (T1D) in Spain and one of the highest in Europe. HLA accounts for half of the genetic risk of T1D.AimsTo characterize the classical HLA-DRB1 and HLA-DQB1 alleles in children from Gran Canaria with and without T1D.MethodsWe analyzed classic HLA-DRB1 and HLA-DQB1 alleles in childhood-onset T1D patients (n = 309) and control children without T1D (n = 222) from the island of Gran Canaria. We also analyzed the presence or absence of aspartic acid at position 57 in the HLA-DQB1 gene and arginine at position 52 in the HLA-DQA1 gene. Genotyping of classical HLA-DQB1 and HLA-DRB1 alleles was performed at two-digit resolution using Luminex technology. The chi-square test (or Fisher's exact test) and odds ratio (OR) were computed to assess differences in allele and genotype frequencies between patients and controls. Logistic regression analysis was also used.ResultsMean age at diagnosis of T1D was 7.4 ± 3.6 years (46% female). Mean age of the controls was 7.6 ± 1.1 years (55% female). DRB1*03 (OR = 4.2; p = 2.13–13), DRB1*04 (OR = 6.6; p ≤ 2.00–16), DRB1* 07 (OR = 0.37; p = 9.73–06), DRB1*11 (OR = 0.17; p = 6.72–09), DRB1*12, DRB1*13 (OR = 0.38; p = 1.21–05), DRB1*14 (OR = 0.0; p = 0.0024), DRB1*15 (OR = 0.13; p = 7.78–07) and DRB1*16 (OR = 0.21; p = 0.003) exhibited significant differences in frequency between groups. Among the DQB1* alleles, DQB1*02 (OR: 2.3; p = 5.13–06), DQB1*03 (OR = 1.7; p = 1.89–03), DQB1*05 (OR = 0.64; p = 0.027) and DQB1*06 (OR = 0.19; p = 6.25–14) exhibited significant differences. A total of 58% of the studied HLA-DQB1 genes in our control population lacked aspartic acid at position 57.ConclusionsIn this population, the overall distributions of the HLA-DRB1 and HLA-DQB1 alleles are similar to those in other European populations. However, the frequency of the non-Asp-57 HLA-DQB1 molecules is greater than that in other populations with a lower incidence of T1D. Based on genetic, historical and epidemiological data, we propose that a common genetic background might help explain the elevated pediatric T1D incidence in the Canary Islands, North-Africa and middle eastern countries.

Selection with two alleles of X-linkage and its application to the fitness component analysis of OdsH in Drosophila.

In organisms with the XY sex-determination system, there is an imbalance in the inheritance and transmission of the X chromosome between males and females. Unlike an autosomal allele, an X-linked recessive allele in a female will have phenotypic effects on its male counterpart. Thus, genes located on the X chromosome are of particular interest to researchers in molecular evolution and genetics. Here we present a model for selection with two alleles of X-linkage to understand fitness components associated with genes on the X chromosome. We apply this model to the fitness analysis of an X-linked gene, OdsH (16D), in the fruit fly Drosophila melanogaster. The function of OdsH is involved in sperm production and the gene is rapidly evolving under positive selection. Using site-directed gene targeting, we generated functional and defective OdsH variants tagged with the eye-color marker gene white. We compare the allele frequency changes of the two OdsH variants, each directly competing against a wild-type OdsH allele in concurrent but separate experimental populations. After 20 generations, the two genetically modified OdsH variants displayed a 40% difference in allele frequencies, with the functional OdsH variant demonstrating an advantage over the defective variant. Using maximum likelihood estimation, we determined the fitness components associated with the OdsH alleles in males and females. Our analysis revealed functional aspects of the fitness determinants associated with OdsH, and that sex-specific fertility and viability consequences both contribute to selection on an X-linked gene.

Haplotype-Aware Detection of SERPINA1 Variants by Nanopore Sequencing

Alpha-1 antitrypsin (AAT) is an acute-phase reactant with immunomodulatory properties that mainly inhibits neutrophil elastase. Low serum levels cause AAT deficiency (AATD), an underdiagnosed condition that predisposes to pulmonary and hepatic diseases. The SERPINA1 gene, which encodes AAT, contains more than 500 variants. PI*Z and PI*S alleles are the most diagnosed causes of AATD, but the role of the SERPINA1 haplotypes in AAT function remains unknown. SERPINA1 gene was PCR amplified from 94 asthma patients, using primers with tails for indexing. Sequencing libraries were loaded into a MinION-Mk1C, and MinKNOW was used for basecalling and demultiplexing. Nanofilt and Minimap2 were used for filtering and mapping/alignment. Variant calling/phasing were performed with PEPPER-Margin-DeepVariant. SERPINA1 gene was 100% covered for all samples, with a minimum sequencing depth of 500X. 75 single nucleotide variants and 4 indels were detected, with 45 and 2 of them highly polymorphic (MAF>0.1), respectively. Nine of the SNVs showed differences in allele frequencies when compared with the overall Spanish population. More than 90% of heterozygous SNVs were phased, yielding 91 and 58 different haplotypes for each SERPINA1 amplified region. Haplotype-based Linkage Disequilibrium (LD) analysis suggests that a recombination hotspot could generate variation in the SERPINA1 gene. The proposed workflow enables haplotype-aware genotyping of the SERPINA1 gene by nanopore sequencing, which will allow the development of novel AATD diagnostic strategies.

Molecular characteristics of NPM1 mutations in AML patients using targeted NGS

ABSTRACT Background Acute myeloid leukemia (AML) is a clonal hematopoietic stem cell malignancy characterized by the accumulation of myeloid progenitor cells with arrested differentiation, leading to the suppression of normal hematopoiesis. The disease exhibits significant heterogeneity, with less than 30% five-year overall survival. Nucleophosmin 1 (NPM1) is the most commonly mutated gene in adult AML, found in approximately 25–35% of patients, and is recognized as a distinct subtype by the WHO. Methods The mutational status of NPM1 was assessed using the Oncomine Myeloid research panel on the Ion5S NGS platform (Thermo Fisher Scientific, USA). Results In our AML cohort, NPM1 was the most frequently mutated gene (75%). Indel mutations in the NPM1 gene, frequently resulting in frameshift consequences, show a statistically significant difference in variant allele frequency (VAF) compared to other mutation types. Specifically, NPM1-mutated cases exhibit a VAF that is positively correlated with initial bone marrow (BM) blast counts. Univariate logistic regression analysis reveals that a high VAF is significantly associated with non-complete remission (Non-CR), while a low VAF is significantly associated with complete remission (CR), indicating a statistically significant difference in outcomes (p = 0.012). Conclusion Targeted NGS technology enables the simultaneous analysis of multiple AML-relevant genes, offering a comprehensive mutational profile that supports risk stratification, diagnosis, and personalized treatment. Our findings highlight the significant impact of NPM1 mutations on patient outcomes, revealing their molecular characteristics and their correlation with different clinical parameters.

QTL-Seq identified a genomic region on chromosome 1 for soil-salinity tolerance in F2 progeny of Thai salt-tolerant rice donor line "Jao Khao".

Owing to advances in high-throughput genome sequencing, QTL-Seq mapping of salt tolerance traits is a major platform for identifying soil-salinity tolerance QTLs to accelerate marker-assisted selection for salt-tolerant rice varieties. We performed QTL-BSA-Seq in the seedling stage of rice from a genetic cross of the extreme salt-sensitive variety, IR29, and "Jao Khao" (JK), a Thai salt-tolerant variety. A total of 462 F2 progeny grown in soil and treated with 160 mM NaCl were used as the QTL mapping population. Two high- and low-bulk sets, based on cell membrane stability (CMS) and tiller number at the recovery stage (TN), were equally sampled. The genomes of each pool were sequenced, and statistical significance of QTL was calculated using QTLseq and G prime (G') analysis, which is based on calculating the allele frequency differences or Δ(SNP index). Both methods detected the overlapping interval region, wherein CMS-bulk was mapped at two loci in the 38.41-38.85 Mb region with 336 SNPs on chromosome 1 (qCMS1) and the 26.13-26.80 Mb region with 1,011 SNPs on chromosome 3 (qCMS3); the Δ(SNP index) peaks were -0.2709 and 0.3127, respectively. TN-bulk was mapped at only one locus in the overlapping 38.26-38.95 Mb region on chromosome 1 with 575 SNPs (qTN1) and a Δ(SNP index) peak of -0.3544. These identified QTLs in two different genetic backgrounds of segregating populations derived from JK were validated. The results confirmed the colocalization of the qCMS1 and qTN1 traits on chromosome 1. Based on the CMS trait, qCMS1/qTN1 stably expressed 6%-18% of the phenotypic variance in the two validation populations, while qCMS1/qTN1 accounted for 16%-20% of the phenotypic variance in one validation population based on the TN trait. The findings confirm that the CMS and TN traits are tightly linked to the long arm of chromosome 1 rather than to chromosome 3. The validated qCMS-TN1 QTL can be used for gene/QTL pyramiding in marker-assisted selection to expedite breeding for salt resistance in rice at the seedling stage.

The Quantitative Genetics of Human Disease: 2 Polygenic Risk Scores

In this the second of an anticipated four papers, we examine polygenic risk scores from a quantitative genetics perspective. In its most simplistic form, a polygenic risk score (PRS) analysis involves estimating the genetic effects of alleles in one study and then using those estimates to predict phenotype in another sample of individuals. Almost since the first application of these types of analyses it has been noted that PRSs often give unexpected and difficult-to-interpret results, particularly when applying effect-size estimates taken from individuals with ancestry very different than those to whom it is applied (applying PRSs across differing populations). To understand these seemingly perplexing observations, we deconstruct the effects of applying valid statistical estimates taken from one population to another when the two populations have differing allele frequencies at the sites contributing effect, when alleles with effects in one population are absent from the other, and finally when there is differing linkage disequilibrium (LD) patterns in the two populations. It will be shown that many of the seemingly most confusing results in the field are natural consequences of these factors. Given our best current understanding of human demographic history, most of the patterns seen in PRS analysis can be predicted as resulting from systematic differences in allele frequency and LD. Put the other way around, the most challenging and confusing results seen in cross population application of PRSs are likely to be the result of allele frequency and LD differences, not differences in the genetic effects of individual alleles. PRS analysis is an important tool both for understanding the genetic basis of complex phenotypes and, potentially, for identifying individuals at risk of developing disease before such disease manifests. As such it has the potential to be among the most important analysis frameworks in human genetics. Nevertheless, when a PRS is trained in people with one ancestry and then applied to people with another, the PRS’s behavior is often unpredictable, and sometimes is seemingly perverse. PRS distributions are often nearly non-overlapping between individuals with differing ancestry, i.e., odds ratios for unaffected people with one ancestry might be vastly larger than affected individuals from another. The correlation between a PRS and known phenotype might differ substantially, and sometimes the correlation is higher among people with ancestry different than the one used to create the PRS. Naively, one might conclude from these observations that the genetic basis of traits differs substantially among people of differing ancestry, and that the behavior of a PRS is difficult to predict when applied to new study populations. Differing definitions of genetic effect sizes are discussed, and key observations are made. It is shown that when populations differ in allele frequency, a locus affecting phenotype could have equal differences in allelic (additive) effects or equal additive variances, but not both. They cannot have equal additive effects, equal allelic penetrances, or equal odds ratios. PRS is defined, and its moments are derived. The effect of differing allele frequency and LD patterns is described. Perplexing PRS observations are discussed in light of theory and human demographic history. Suggestions for best practices for PRS construction are made. The most confusing results seen in cross population application of PRSs are often the predictable result of allele frequency and LD differences. There is relatively little evidence for systematic differences in the genetic basis of disease in individuals of differing ancestry, other than that which results from environmental, allele frequency, and LD differences.

Genome-wide SNP assessment of contemporary European red deer genetic structure highlights the distinction of peripheral populations and the main admixture zones in Europe.

Genome-wide technologies open up new possibilities to clarify questions on genetic structure and phylogeographic history of taxa previously studied with microsatellite loci and mitochondrial sequences. Here, we used 736 individual red deer (Cervus elaphus) samples genotyped at 35,701 single nucleotide polymorphism loci (SNPs) to assess the population structure of the species throughout Europe. The results identified 28 populations, with higher degrees of genetic distinction in peripheral compared to mainland populations. Iberian red deer show high genetic differentiation, with lineages in Western and Central Iberia maintaining their distinctiveness, which supports separate refugial ranges within Iberia along with little recent connection between Iberian and the remaining Western European populations. The Norwegian population exhibited the lowest variability and the largest allele frequency differences from mainland European populations, compatible with a history of bottlenecks and drift during post-glacial colonization from southern refugia. Scottish populations showed high genetic distance from the mainland but high levels of diversity. Hybrid zones were found between Eastern and Western European lineages in Central Europe as well as in the Pyrenees, where red deer from France are in close contact with Iberian red deer. Anthropogenic restocking has promoted the Pyrenean contact zone, admixture events in populations on the Isle of Rum and in the Netherlands, and at least partly the admixture of the two main lineages in central-eastern Europe. Our analysis enabled detailed resolution of population structure of a large mammal widely distributed throughout Europe and contributes to resolving the evolutionary history, which can also inform conservation and management policies.

Cardiovascular Pharmacogenetics: From Discovery of Genetic Association to Clinical Adoption of Derived Test.

Recent breakthroughs in human genetics and in information technologies have markedly expanded our understanding at the molecular level of the response to drugs, i.e., pharmacogenetics (PGx), across therapy areas. This review is restricted to PGx for cardiovascular (CV) drugs. First, we examined the PGx information in the labels approved by regulatory agencies in Europe, Japan, and North America and related recommendations from expert panels. Out of 221 marketed CV drugs, 36 had PGx information in their labels approved by one or more agencies. The level of annotations and recommendations varied markedly between agencies and expert panels. Clopidogrel is the only CV drug with consistent PGx recommendation (i.e., "actionable"). This situation prompted us to dissect the steps from discovery of a PGx association to clinical translation. We found 101 genome-wide association studies that investigated the response to CV drugs or drug classes. These studies reported significant associations for 48 PGx traits mapping to 306 genes. Six of these 306 genes are mentioned in the corresponding PGx labels or recommendations for CV drugs. Genomic analyses also highlighted the wide between-population differences in risk allele frequencies and the individual load of actionable PGx variants. Given the high attrition rate and the long road to clinical translation, additional work is warranted to identify and validate PGx variants for more CV drugs across diverse populations and to demonstrate the utility of PGx testing. To that end, pre-emptive PGx combining genomic profiling with electronic medical records opens unprecedented opportunities to improve healthcare, for CV diseases and beyond. SIGNIFICANCE STATEMENT: Despite spectacular breakthroughs in human molecular genetics and information technologies, consistent evidence supporting PGx testing in the cardiovascular area is limited to a few drugs. Additional work is warranted to discover and validate new PGx markers and demonstrate their utility. Pre-emptive PGx combining genomic profiling with electronic medical records opens unprecedented opportunities to improve healthcare, for CV diseases and beyond.

MiR-146a rs2910164 (G/C) variant may predict morbid obesity risk in adults

Obesity is a common public health problem associated with serious, life-threatening complications. MicroRNAs (miRs) have modulating roles in the immune and inflammatory systems. Therefore, this study aimed to analyze the relationship between miR-146a and morbid obesity (MO) in a Turkish population. In this study, a total of 258 subjects (110 patients with MO and 148 controls) were genotyped by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to analyze miR-146a rs2910164. Then, we examined the patients as males and females separately. The results of the analyses were evaluated for statistical significance. There was a significant difference in genotype and allele frequencies of miR-146a rs2910164 between patients with MO and control individuals. miR-146a rs2910164 CC genotype and C allele were shown to increase in the MO patients’ group compared to the control group (p = 0.000, p = 0.000, respectively). Also, the C allele was higher in both female and male patients compared to controls (p = 0.000, p = 0.000, respectively). High differences were also observed when the patients and the controls were compared according to CC versus GG + GC and GG versus GC + CC (p = 0.000, p = 0.000, respectively). A significant difference was found between the female/male patients and the female/male controls in terms of GG + GC versus CC (p = 0.000, p = 0.000, respectively). To the best of our knowledge, this is the first study to investigate the relationship between this variant and MO in Turkey. Our results showed that miR-146a rs2910164 is a valuable biomarker that can be used to distinguish between patients with MO and the healthy population. The findings can be extended by increasing the sample sizes with diverse ethnicities.

An atlas of genetic effects on the monocyte methylome across European and African populations.

Elucidating the genetic architecture of DNA methylation (DNAm) is crucial for decoding the etiology of complex diseases. However, current epigenomic studies often suffer from incomplete coverage of methylation sites and the use of tissues containing heterogeneous cell populations. To address these challenges, we present a comprehensive human methylome atlas based on deep whole-genome bisulfite sequencing (WGBS) and whole-genome sequencing (WGS) of purified monocytes from 298 European Americans (EA) and 160 African Americans (AA) in the Louisiana Osteoporosis Study. Our atlas enables the analysis of over 25 million DNAm sites. We identified 1,383,250 and 1,721,167 methylation quantitative trait loci (meQTLs) in cis -regions for EA and AA populations, respectively, with 880,108 sites shared between ancestries. While cis -meQTLs exhibited population-specific patterns, primarily due to differences in minor allele frequencies, shared cis -meQTLs showed high concordance across ancestries. Notably, cis -heritability estimates revealed significantly higher mean values in the AA population (0.09) compared to the EA population (0.04). Furthermore, we developed population-specific DNAm imputation models using Elastic Net, enabling methylome-wide association studies (MWAS) for 1,976,046 and 2,657,581 methylation sites in EA and AA, respectively. The performance of our MWAS models was validated through a systematic multi-ancestry analysis of 41 complex traits from the Million Veteran Program. Our findings bridge the gap between genomics and the monocyte methylome, uncovering novel methylation-phenotype associations and their transferability across diverse ancestries. The identified meQTLs, MWAS models, and data resources are freely available at www.gcbhub.org and https://osf.io/gct57/ .

Mapping Epigenetic Gene Variant Dynamics: Comparative Analysis of Frequency, Functional Impact and Trait Associations in African and European Populations.

Epigenetic modifications influence gene expression levels, impact organismal traits, and play a role in the development of diseases. Therefore, variants in genes involved in epigenetic processes are likely to be important in disease susceptibility, and the frequency of variants may vary between populations with African and European ancestries. Here, we analyse an integrated dataset to define the frequencies, associated traits, and functional impact of epigenetic gene variants among individuals of African and European ancestry represented in the UK Biobank. We find that the frequencies of 88.4% of epigenetic gene variants significantly differ between these groups. Furthermore, we find that the variants are associated with many traits and diseases, and some of these associations may be population-specific owing to allele frequency differences. Additionally, we observe that variants associated with traits are significantly enriched for quantitative trait loci that affect DNA methylation, chromatin accessibility, and gene expression. We find that methylation quantitative trait loci account for 71.2% of the variants influencing gene expression. Moreover, variants linked to biomarker traits exhibit high correlation. We therefore conclude that epigenetic gene variants associated with traits tend to differ in their allele frequencies among African and European populations and are enriched for QTLs.

Association of VEGFR1, VEGFR2 and VEGFR3 polymorphisms with esophageal cancer risk: a case–control study

BackgroundEsophageal cancer is the eleventh most common cancer and is the seventh leading cause of mortality worldwide. Vascular endothelial growth factor (VEGF) and its receptors pathway are a key regulator of angiogenesis and play an important role in carcinogenesis. The aim of current study was to evaluate the association of five VEGFR polymorphisms with esophageal cancer risk in patients from Punjab, North-west India.MethodsThis case–control study included 310 esophageal cancer patients and 325 age and gender matched healthy controls. VEGFR1-710C/T, VEGFR2-604 T/C (rs2071559), VEGFR2 1192 G/A (rs2305948), VEGFR2 1719A/T (rs1870377) and VEGFR3 (rs72816988) polymorphisms were genotyped by using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method. Restriction digestion products were analyzed on 2.4% agarose gel and genotype was assigned to each sample on the basis of fragments obtained after digestion. Randomly 10% samples were repeated by Sanger sequencing to revalidate the results.ResultsThere was a significant association of CT genotype (OR = 0.28; 95%CI, 0.10–0.76; p = 0.01) and T allele (OR = 0.28; 95%CI, 0.10–0.77; p = 0.01) of VEGFR1-710C/T polymorphism with decreased risk of esophageal cancer. TC genotype of VEGFR2-604 T/C (OR = 0.66; 95%CI, 0.44–0.97; p = 0.03) and GA genotype of VEGFR2 1192G/A (OR = 0.54; 95%CI, 0.31–0.95; p = 0.03) polymorphisms were significantly associated with decreased risk of esophageal cancer. There was no significant difference in allele and genotype frequency of VEGFR2 1719A/T and VEGFR3 (rs72816988) polymorphisms between esophageal cancer patients and controls (p > 0.05). Haplotype analysis revealed that haplotype C-604A1719A1192 was significantly associated with the decreased esophageal cancer risk (OR = 0.44; 95%CI, 0.23–0.84; p = 0.01).ConclusionVEGFR1-710C/T, VEGFR2-604 T/C and VEGFR2 1192G/A polymorphisms were associated with the decreased risk of esophageal cancer in patients from Punjab, North-west India.Graphical abstract

Association between angiotensin-converting enzyme gene insertion/deletion polymorphism and cognition impairment in patients with schizophrenia.

Several lines of evidence indicate that an insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene (ACE) gene may be involved in the pathogenesis of schizophrenia and cognitive impairment. However, the relationship between ACE I/D polymorphism and cognitive impairment in patients with schizophrenia remains unclear. The aim of this study was to examine whether ACE gene I/D polymorphism contributed to cognitive impairment in Chinese patients with schizophrenia, and whether the association between clinical symptoms and cognitive impairment depended on different ACE genotypes. The ACE I/D polymorphism was genotyped in 928 schizophrenia patients and 325 healthy controls using a case-control design. The severity of psychopathological symptoms was assessed using the Positive and Negative Syndrome Scale (PANSS). Cognitive functioning was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). There were significant differences in genotype and allele frequencies of the ACE I/D polymorphism between patients and healthy controls (both P < 0.01). After controlling for demographic characteristics, patients who are homozygous carriers of D and I performed worse on the RBANS attention index than heterozygous carriers (P = 0.009). In addition, attention index score was negatively correlated with PANSS negative symptom score in patients of all genotypes (all P < 0.05), and positively correlated with positive symptom score only in the I/I genotype (P = 0.005). These findings suggest that ACE I/D gene variants play a role in susceptibility to schizophrenia, specific cognitive impairment and the association between clinical symptoms and cognitive impairment in schizophrenia patients.