scholarly journals Decreased retinal vascular complexity is an early biomarker of MI supported by a shared genetic control.

Author(s):  
Ana Villaplana Velasco ◽  
Justin Engelmann ◽  
Konrad Rawlik ◽  
Oriol Canela-Xandri ◽  
Claire Tochel ◽  
...  

There is increasing evidence that the complexity of the retinal vasculature (measured as fractal dimension, Df) might offer earlier insights into the progression of coronary artery disease (CAD) before traditional biomarkers can be detected. This association could be partly explained by a common genetic basis; however, the genetic component of Df is poorly understood. We present here a genome-wide association study (GWAS) aimed to elucidate the genetic component of Df and to analyse its relationship with CAD. To this end, we obtained Df from retinal fundus images and genotyping information from ~38,000 white-British participants in the UK Biobank. We discovered 9 loci associated with Df, previously reported in pigmentation, retinal width and tortuosity, hypertension, and CAD studies. Significant negative genetic correlation estimates endorse the inverse relationship between Df and CAD, and between Df and myocardial infarction (MI), one of CAD fatal outcomes. This strong association motivated us to developing a MI predictive model combining clinical information, Df, a CAD polygenic risk score and using a random forest algorithm. Internal cross validation evidenced a considerable improvement in the area under the curve (AUC) of our predictive model (AUC=0.770) when comparing with an established risk model, SCORE, (AUC=0.719). Our findings shed new light on the genetic basis of Df, unveiling a common control with CAD, and highlights the benefits of its application in individualised MI risk prediction.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Juniper A. Lake ◽  
Jack C. M. Dekkers ◽  
Behnam Abasht

AbstractWooden breast (WB) and white striping (WS) are highly prevalent and economically damaging muscle disorders of modern commercial broiler chickens characterized respectively by palpable firmness and fatty white striations running parallel to the muscle fiber. High feed efficiency and rapid growth, especially of the breast muscle, are believed to contribute to development of such muscle defects; however, their etiology remains poorly understood. To gain insight into the genetic basis of these myopathies, a genome-wide association study was conducted using a commercial crossbred broiler population (n = 1193). Heritability was estimated at 0.5 for WB and WS with high genetic correlation between them (0.88). GWAS revealed 28 quantitative trait loci (QTL) on five chromosomes for WB and 6 QTL on one chromosome for WS, with the majority of QTL for both myopathies located in a ~ 8 Mb region of chromosome 5. This region has highly conserved synteny with a portion of human chromosome 11 containing a cluster of imprinted genes associated with growth and metabolic disorders such as type 2 diabetes and Beckwith-Wiedemann syndrome. Candidate genes include potassium voltage-gated channel subfamily Q member 1 (KCNQ1), involved in insulin secretion and cardiac electrical activity, lymphocyte-specific protein 1 (LSP1), involved in inflammation and immune response.


Author(s):  
Priyanka Gupta ◽  
Hafssa Kabbaj ◽  
Khaoula El Hassouni ◽  
Marco Maccaferri ◽  
Miguel Sabchez-Garcia ◽  
...  

Flowering time is a critical stage for crop development as it regulates the ability of plants to adapt to an environment. To understand the genetic control of flowering time, a genome wide association study (GWAS) was conducted to identify the genomic regions associated with the control of this trait in durum wheat (Triticum durum Desf.). A total of 96 landraces and 288 modern lines were evaluated for days to heading, growing degree days, and accumulated day length at flowering across 13 environments spread across Morocco, Lebanon, Mauritania, and Senegal. These environments were grouped into four pheno-environments based on temperatures, day length and other climatic variables. Genotyping with 35K Axiom array generated 7,652 polymorphic SNPs in addition to 3 KASP markers associated to known flowering genes. In total, 34 significant QTLs were identified in both landraces and modern lines. Some QTLs had strong association with already known regulatory photoperiod genes, Ppd-A and Ppd-B and vernalization genes Vrn-A1, and Vrn3. However, these loci explained only 5 to 20% of variance for days to heading. Seven QTLs overlapped between the two germplasm groups in which Q.ICD.Eps-03 and Q.ICD.Vrn-17 consistently affected flowering time in all the pheno-environments, while Q.ICD.Eps-11 and Q.ICD.Ppd-12 were significant only in two pheno-environments and the combined analysis across all environments. These results help clarify the genetic mechanism controlling flowering time in durum wheat and show some clear distinctions to what is known for common wheat (Triticum aestivum L.)


2020 ◽  
Vol 6 (22) ◽  
pp. eaaz7835 ◽  
Author(s):  
Sungwon Jeon ◽  
Youngjune Bhak ◽  
Yeonsong Choi ◽  
Yeonsu Jeon ◽  
Seunghoon Kim ◽  
...  

We present the initial phase of the Korean Genome Project (Korea1K), including 1094 whole genomes (sequenced at an average depth of 31×), along with data of 79 quantitative clinical traits. We identified 39 million single-nucleotide variants and indels of which half were singleton or doubleton and detected Korean-specific patterns based on several types of genomic variations. A genome-wide association study illustrated the power of whole-genome sequences for analyzing clinical traits, identifying nine more significant candidate alleles than previously reported from the same linkage disequilibrium blocks. Also, Korea1K, as a reference, showed better imputation accuracy for Koreans than the 1KGP panel. As proof of utility, germline variants in cancer samples could be filtered out more effectively when the Korea1K variome was used as a panel of normals compared to non-Korean variome sets. Overall, this study shows that Korea1K can be a useful genotypic and phenotypic resource for clinical and ethnogenetic studies.


Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 234 ◽  
Author(s):  
Joanne R Chapman ◽  
Maureen A Dowell ◽  
Rosanna Chan ◽  
Robert L Unckless

Dissecting the genetic basis of natural variation in disease response in hosts provides insights into the coevolutionary dynamics of host-pathogen interactions. Here, a genome-wide association study of Drosophila melanogaster survival after infection with the Gram-positive entomopathogenic bacterium Enterococcus faecalis is reported. There was considerable variation in defense against E. faecalis infection among inbred lines of the Drosophila Genetics Reference Panel. We identified single nucleotide polymorphisms associated with six genes with a significant (p < 10−08, corresponding to a false discovery rate of 2.4%) association with survival, none of which were canonical immune genes. To validate the role of these genes in immune defense, their expression was knocked-down using RNAi and survival of infected hosts was followed, which confirmed a role for the genes krishah and S6k in immune defense. We further identified a putative role for the Bomanin gene BomBc1 (also known as IM23), in E. faecalis infection response. This study adds to the growing set of association studies for infection in Drosophila melanogaster and suggests that the genetic causes of variation in immune defense differ for different pathogens.


2019 ◽  
Vol 36 (12) ◽  
pp. 2890-2905 ◽  
Author(s):  
Christos Vlachos ◽  
Robert Kofler

Abstract Evolve and resequence (E&R) studies are frequently used to dissect the genetic basis of quantitative traits. By subjecting a population to truncating selection for several generations and estimating the allele frequency differences between selected and nonselected populations using next-generation sequencing (NGS), the loci contributing to the selected trait may be identified. The role of different parameters, such as, the population size or the number of replicate populations has been examined in previous works. However, the influence of the selection regime, that is the strength of truncating selection during the experiment, remains little explored. Using whole genome, individual based forward simulations of E&R studies, we found that the power to identify the causative alleles may be maximized by gradually increasing the strength of truncating selection during the experiment. Notably, such an optimal selection regime comes at no or little additional cost in terms of sequencing effort and experimental time. Interestingly, we also found that a selection regime which optimizes the power to identify the causative loci is not necessarily identical to a regime that maximizes the phenotypic response. Finally, our simulations suggest that an E&R study with an optimized selection regime may have a higher power to identify the genetic basis of quantitative traits than a genome-wide association study, highlighting that E&R is a powerful approach for finding the loci underlying complex traits.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Wei Xu ◽  
Di Wu ◽  
Tianquan Yang ◽  
Chao Sun ◽  
Zaiqing Wang ◽  
...  

Abstract Background Castor bean (Ricinus communis L.) is an important oil crop, which belongs to the Euphorbiaceae family. The seed oil of castor bean is currently the only commercial source of ricinoleic acid that can be used for producing about 2000 industrial products. However, it remains largely unknown regarding the origin, domestication, and the genetic basis of key traits of castor bean. Results Here we perform a de novo chromosome-level genome assembly of the wild progenitor of castor bean. By resequencing and analyzing 505 worldwide accessions, we reveal that the accessions from East Africa are the extant wild progenitors of castor bean, and the domestication occurs ~ 3200 years ago. We demonstrate that significant genetic differentiation between wild populations in Kenya and Ethiopia is associated with past climate fluctuation in the Turkana depression ~ 7000 years ago. This dramatic change in climate may have caused the genetic bottleneck in wild castor bean populations. By a genome-wide association study, combined with quantitative trait locus analysis, we identify important candidate genes associated with plant architecture and seed size. Conclusions This study provides novel insights of domestication and genome evolution of castor bean, which facilitates genomics-based breeding of this important oilseed crop and potentially other tree-like crops in future.


Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1722
Author(s):  
Byeong Yong Jeong ◽  
Yoonjung Lee ◽  
Yebin Kwon ◽  
Jee Hye Kim ◽  
Tae-Ho Ham ◽  
...  

A genome-wide association study (GWAS) was used to investigate the genetic basis of chilling tolerance in a collection of 117 rice accessions, including 26 Korean landraces and 29 weedy rices, at the reproductive stage. To assess chilling tolerance at the early young microspore stage, plants were treated at 12 °C for 5 days, and tolerance was evaluated using seed set fertility. GWAS, together with principal component analysis and kinship matrix analysis, revealed five quantitative trait loci (QTLs) associated with chilling tolerance on chromosomes 3, 6, and 7. The percentage of phenotypic variation explained by the QTLs was 11–19%. The genomic region underlying the QTL on chromosome 3 overlapped with a previously reported QTL associated with spikelet fertility. Subsequent bioinformatic and haplotype analyses suggested three candidate chilling-tolerance genes within the QTL linkage disequilibrium block: Os03g0305700, encoding a protein similar to peptide chain release factor 2; Os06g0495700, encoding a beta tubulin, autoregulation binding-site-domain-containing protein; and Os07g0137800, encoding a protein kinase, core-domain-containing protein. Further analysis of the detected QTLs and the candidate chilling-tolerance genes will facilitate strategies for developing chilling-tolerant rice cultivars in breeding programs.


2017 ◽  
Author(s):  
Sébastien Thériault ◽  
Nathalie Gaudreault ◽  
Maxime Lamontagne ◽  
David Messika-Zeitoun ◽  
Marie-Annick Clavel ◽  
...  

AbstractCalcific aortic valve stenosis (CAVS) is a common and life-threatening heart disease with no drug that can stop or delay its progression. Elucidating the genetic factors underpinning CAVS is an urgent priority to find new therapeutic targets1. Major landmarks in genetics of CAVS include the discoveries of NOTCH12 and LPA3. However, genetic variants in these genes accounted for a small number of cases and low population-attributable risk. Here we mapped a new susceptibility locus for CAVS on chromosome 1p21.2 and identified PALMD (palmdelphin) as the causal gene. PALMD was revealed using a transcriptome-wide association study (TWAS)4, which combines a genome-wide association study (GWAS) of 1,009 cases and 1,017 ethnically-matched controls with the first large-scale expression quantitative trait loci (eQTL) mapping study on human aortic valve tissues (n=233). The CAVS risk alleles and increasing disease severity were both associated with lowered mRNA expression levels of PALMD in valve tissues. The top variant explained up to 12.5% of the population-attributable risk and showed similar effect and strong association with CAVS (P=1.53 × 10−10) in UK Biobank comparing 1,391 cases and 352,195 controls. The identification of PALMD as a susceptibility gene for CAVS provides new insights about the genetic nature of this disease and opens new avenues to investigate its etiology and develop much-needed therapeutic options.


2021 ◽  
Author(s):  
Victor Nauffal ◽  
Valerie N Morrill ◽  
Sean J Jurgens ◽  
Seung Hoan Choi ◽  
Amelia W Hall ◽  
...  

Background: Rare sequence variation in genes underlying the long QT syndrome (LQTS) and common polygenic variation influence QT interval duration. It is unclear how rare and common variation contribute to QT interval duration in the general population. Objectives: Investigate monogenic and polygenic contributions to QT interval duration and the role of polygenic variation in modulating phenotypic expression of rare monogenic variation. Methods: We performed a genome wide association study (GWAS) of QTc duration in 44,979 United Kingdom Biobank (UKBB) participants and created a polygenic risk score (PRS). The PRS was validated in 39,800 independent UKBB participants. Among 26,976 participants with whole genome sequencing and ECG data in the TransOmics for Precision Medicine (TOPMed) program, we identified 160 carriers of putative pathogenic rare variants in 10 LQTS genes. We examined QTc associations with the PRS and with LQTS rare variants in TOPMed. Results: Twenty independent loci (4 novel) were identified by GWAS. The PRS comprising 565 common variants was significantly associated with QTc duration in TOPMed (p=1.1x10-64). Carriers of LQTS rare variants had longer QTc intervals than non-carriers (deltaQTc=10.9 ms [7.4-14.4] for all LQTS genes; deltaQTc=26.5 ms [20.7-32.3] for KCNQ1, KCNH2 and SCN5A). 16.7% of individuals with QTc>480 ms carried either a rare variant in a LQTS gene or had a PRS in the top decile (3.4% monogenic, 13.6% top decile of PRS). We observed a greater effect of rare variants on the QTc among individuals with a higher polygenic risk (lowest PRS tertile:deltaQTccarrier/non-carrier=4.8 ms [-1.2-10.7];highest PRS tertile:deltaQTccarrier/non-carrier=18.9 ms [12.8-25.1];p-interaction=0.001). Conclusions: QTc duration is influenced by both rare variants in established LQTS genes and polygenic risk. The phenotypic expression of monogenic variation is modulated by polygenic variation. Nevertheless, over 80% of individuals with prolonged QTc do not carry a rare monogenic variant or polygenic risk equivalent.


Animals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 260 ◽  
Author(s):  
Bo Zhu ◽  
Qinghe Li ◽  
Ranran Liu ◽  
Maiqing Zheng ◽  
Jie Wen ◽  
...  

Presently, the heterophil-to-lymphocyte (H/L) ratio is being studied extensively as a disease resistance trait. Through intricate mechanisms to identify and destroy pathogenic microorganisms, heterophils play a pivotal role in the immune defense systems of avian species. To reveal the genetic basis and molecular mechanisms affecting the H/L ratio, phenotypic and H/L data from 1650 white feather chicken broilers were used in performing a genome-wide association study. A self-developed, chicken-specific 55K chip was used for heterophils, lymphocytes, and H/L classification, according to individual genomic DNA profiles. We identified five significant single nucleotide polymorphisms (SNPs) when the genome-wide significance threshold was set to 5% (p < 2.42 × 10−6). A total of 15 SNPs obtained seemingly significant levels (p < 4.84 × 10−5). Gene annotation indicated that CARD11 (Caspase recruitment domain family member 11), BRIX1 (Biogenesis of ribosomes BRX1), and BANP (BTG3 associated nuclear protein) play a role in H/L-associated cell regulation and potentially constitute candidate gene regions for cellular functions dependent on H/L ratios. These results lay the foundation for revealing the genetic basis of disease resistance and future marker-assisted selection for disease resistance.


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