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1.
BMC Plant Biol ; 19(1): 328, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337341

RESUMO

BACKGROUND: To efficiently protect and exploit germplasm resources for marker development and breeding purposes, we must accurately depict the features of the tea populations. This study focuses on the Camellia sinensis (C. sinensis) population and aims to (i) identify single nucleotide polymorphisms (SNPs) on the genome level, (ii) investigate the genetic diversity and population structure, and (iii) characterize the linkage disequilibrium (LD) pattern to facilitate next genome-wide association mapping and marker-assisted selection. RESULTS: We collected 415 tea accessions from the Origin Center and analyzed the genetic diversity, population structure and LD pattern using the genotyping-by-sequencing (GBS) approach. A total of 79,016 high-quality SNPs were identified; the polymorphism information content (PIC) and genetic diversity (GD) based on these SNPs showed a higher level of genetic diversity in cultivated type than in wild type. The 415 accessions were clustered into three groups by STRUCTURE software and confirmed using principal component analyses (PCA)-wild type, cultivated type, and admixed wild type. However, unweighted pair group method with arithmetic mean (UPGMA) trees indicated the accessions should be grouped into more clusters. Further analyses identified four groups, the Pure Wild Type, Admixed Wild Type, ancient landraces and modern landraces using STRUCTURE, and the results were confirmed by PCA and UPGMA tree method. A higher level of genetic diversity was detected in ancient landraces and Admixed Wild Type than that in the Pure Wild Type and modern landraces. The highest differentiation was between the Pure Wild Type and modern landraces. A relatively fast LD decay with a short range (kb) was observed, and the LD decays of four inferred populations were different. CONCLUSIONS: This study is, to our knowledge, the first population genetic analysis of tea germplasm from the Origin Center, Guizhou Plateau, using GBS. The LD pattern, population structure and genetic differentiation of the tea population revealed by our study will benefit further genetic studies, germplasm protection, and breeding.


Assuntos
Camellia sinensis/genética , China , Variação Genética/genética , Estudo de Associação Genômica Ampla , Técnicas de Genotipagem , Desequilíbrio de Ligação/genética , Polimorfismo de Nucleotídeo Único/genética , Dinâmica Populacional
3.
BMC Plant Biol ; 19(1): 259, 2019 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-31208337

RESUMO

BACKGROUND: Cultivated rice (Oryza sativa L.) is one of the staple food for over half of the world's population. Thus, improvement of cultivated rice is important for the development of the world. It has been shown that abundant elite genes exist in rice landraces in previous studies. RESULTS: A genome-wide association study (GWAS) performed with EMMAX for 12 agronomic traits measured in both Guangzhou and Hangzhou was carried out using 150 accessions of Ting's core collection selected based on 48 phenotypic traits from 2262 accessions of Ting's collection, the GWAS included more than 3.8 million SNPs. Within Ting's core collection, which has a simple population structure, low relatedness, and rapid linkage disequilibrium (LD) decay, we found 32 peaks located closely to previously cloned genes such as Hd1, SD1, Ghd7, GW8, and GL7 or mapped QTL, and these loci might be natural variations in the cloned genes or QTL which influence potentially agronomic traits. Furthermore, we also detected 32 regions where new genes might be located, and some peaks of these new candidate genes such as the signal on chromosome 11 for heading days were even higher than that of Hd1. Detailed annotation of these significant loci were shown in this study. Moreover, according to the estimated LD decay distance of 100 to 350 kb on the 12 chromosomes in this study, we found 13 identical significant regions in the two locations. CONCLUSIONS: This research provided important information for further mining these elite genes within Ting's core collection and using them for rice breeding.


Assuntos
Oryza/genética , Característica Quantitativa Herdável , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Genes de Plantas/genética , Estudos de Associação Genética , Estudo de Associação Genômica Ampla , Desequilíbrio de Ligação/genética , Locos de Características Quantitativas/genética
4.
Mol Immunol ; 112: 40-50, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31078115

RESUMO

The classical HLA class I genes (HLA Ia) were extensively studied because of their implication in clinical fields and anthropology. Less is known about worldwide genetic diversity and linkage disequilibrium for non-classical HLA class I genes (HLA Ib) and HLA pseudogenes. Notably, HLA-H, which is deleted in a fraction of the population, remains scarcely explored. The aims of this study were 1/ to get further insight into HLA-H genetic diversity and into how this variability potentially affects its expression and 2/ to define HLA Ib worldwide allelic diversity and linkage. Exome sequence data from the 1000 Genomes Project were used to define second field HLA-A, -E, -F, -G and -H typing using PolyPheMe software. Allelic and two-loci haplotype frequencies were estimated using Gene[Rate] software both at worldwide and continental levels. Eleven novel HLA-H alleles identified in exome data were validated by NGS performed on 25 genomic DNA samples from the same cohort. Phylogenetic analysis and frequency distribution of HLA-H alleles revealed three clades, each predominantly represented in Admixed American, European and East Asian populations, African populations and South Asian populations. Among these eleven novel alleles, two potentially encode complete transmembrane HLA proteins. We confirm the high LD between HLA-H and -A, and between HLA-H and -G, and show the three genes have distinct worldwide allelic distribution. Conversely, HLA-E and HLA-F both showed little LD, displayed restricted allelic diversity and practically no difference in their distribution across the planet. Our work thus reveals an unexpectedly high HLA-H genetic diversity, with alleles highly represented in Asia possibly encoding a functional HLA protein. Functional implication of these results remains to be explored, both in physiological and pathological contexts.


Assuntos
Variação Genética/genética , Antígenos HLA-DQ/genética , Haplótipos/genética , Proteína da Hemocromatose/genética , Alelos , Ásia , Grupo com Ancestrais do Continente Asiático/genética , Frequência do Gene/genética , Genes MHC Classe I/genética , Humanos , Desequilíbrio de Ligação/genética , Filogenia
5.
Genet Epidemiol ; 43(5): 577-591, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31045279

RESUMO

It is 100 years since R. A. Fisher proposed that a Mendelian model of genetic variant effects, additive over loci, could explain the patterns of observed phenotypic correlations between relatives. His loci were hypothetical and his model theoretical. It is only about 50 years since the first genetic markers allowed the detection of even variants with major effects on phenotype, and only 20 years since the development of single-nucleotide polymorphism technology provided dense markers over the genome. Then both mappings in defined pedigrees and population-based genome-wide association studies samples allowed the detection of multiple contributing variants of smaller effect. Finally, with methods based on genotypic correlations between individuals, or on allelic associations between loci, the additive heritability contributions of the genome can be estimated from large population samples. In this review we trace, from 1918 to 2018, the analysis of observed phenotypic correlations between relatives to estimate underlying genetic components of traits in human populations. As with studies from 1918 onward, we use height as the example trait where not only data are readily available, but where Fisher's model of large numbers of variants of infinitesimal effect appears to provide a good approximation to reality. However, we also trace the use of phenotypic and genotypic correlations between relatives in mapping causal variants and resolving genetic contributions to more complex human traits. With the availability of DNA sequence data, we can hope to not only estimate the total genetic contribution to a trait, but to resolve effects of individual genetic variants on biological function.


Assuntos
Família , Genoma Humano , Modelos Genéticos , Sequência de Bases , Mapeamento Cromossômico , Marcadores Genéticos , Genética Populacional , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Padrões de Herança/genética , Desequilíbrio de Ligação/genética , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genética , Característica Quantitativa Herdável
6.
Plant Sci ; 283: 157-164, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128685

RESUMO

Combining ability is crucial for parent selection in crop hybrid breeding. Many studies have attempted to provide reliable and quick methods to identify genome regions in parental lines correlating with improved hybrid performance. The local haplotype patterns surrounding densely spaced DNA markers include a large amount of genetic information, and analysis of the relationships between haplotypes and hybrid performance can provide insight into the underlying genome regions which might contribute to enhancing combining ability. Here, we generated 24,403 single-copy, genome-wide SNP loci and calculated the general combining ability (GCA) of 950 hybrids from a diverse panel of 475 pollinators of spring-type canola inbred lines crossed with two testers for days to flowering (DTF) and seed glucosinolate content (GSL). We performed a genome-wide analysis of the haplotypes and detected eight and seven haplotype regions that were significantly associated with the GCA values for DTF and seed GSL, respectively. Additionally, two haplotype blocks containing orthologs of flowering time genes FLOWERING LOCUS T (FT) and FLOWERING LOCUS C (FLC) on chromosome A02 showed additive epistatic interactions influencing flowering time. Moreover, two homoeologous haplotype regions on chromosomes A02 and C02 corresponded to major quantitative trait loci (QTL) for GSL which showed additive effects related to reduction of seed GSL in F1 hybrids. Our study showed that haplotype analysis has the potential to substantially improve the efficiency of hybrid breeding programs.


Assuntos
Brassica napus/genética , Característica Quantitativa Herdável , Brassica napus/crescimento & desenvolvimento , Mapeamento Cromossômico , Flores/crescimento & desenvolvimento , Genes de Plantas/genética , Estudos de Associação Genética , Estudo de Associação Genômica Ampla , Haplótipos/genética , Vigor Híbrido/genética , Desequilíbrio de Ligação/genética , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único/genética
7.
BMC Plant Biol ; 19(1): 147, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30991940

RESUMO

BACKGROUND: Stripe rust (also called yellow rust) is a common and serious fungal disease of wheat (Triticum aestivum L.) caused by Puccinia striiformis f. sp. tritici. The narrow genetic basis of modern wheat cultivars and rapid evolution of the rust pathogen have been responsible for periodic and devastating epidemics of wheat rust diseases. In this study, we conducted a genome-wide association study with 44,059 single nucleotide polymorphism markers to identify loci associated with resistance to stripe rust in 244 Sichuan wheat accessions, including 79 landraces and 165 cultivars, in six environments. RESULTS: In all the field assessments, 24 accessions displayed stable high resistance to stripe rust. Significant correlations among environments were observed for both infection (IT) and disease severity (DS), and high heritability levels were found for both IT and DS. Using mixed linear models, 12 quantitative trait loci (QTLs) significantly associated with IT and/or DS were identified. Two QTLs were mapped on chromosomes 5AS and 5AL and were distant from previously identified stripe rust resistance genes or QTL regions, indicating that they may be novel resistance loci. CONCLUSIONS: Our results revealed that resistance alleles to stripe rust were accumulated in Sichuan wheat germplasm, implying direct or indirect selection for improved stripe rust resistance in elite wheat breeding programs. The identified stable QTLs or favorable alleles could be important chromosome regions in Sichuan wheat that controlled the resistance to stripe rust. These markers can be used molecular marker-assisted breeding of Sichuan wheat cultivars, and will be useful in the ongoing effort to develop new wheat cultivars with strong resistance to stripe rust.


Assuntos
Basidiomycota/fisiologia , Resistência à Doença/genética , Genoma de Planta , Estudo de Associação Genômica Ampla , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Triticum/genética , Triticum/microbiologia , Alelos , Basidiomycota/patogenicidade , Cromossomos de Plantas/genética , Ecótipo , Loci Gênicos , Variação Genética , Desequilíbrio de Ligação/genética , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Triticum/imunologia , Virulência/genética
8.
BMC Plant Biol ; 19(1): 149, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-31003597

RESUMO

BACKGROUND: Wheat is a cool seasoned crop requiring low temperature during grain filling duration and therefore increased temperature causes significant yield reduction. A set of 125 spring wheat genotypes from International Maize and Wheat Improvement Centre (CIMMYT-Mexico) was evaluated for phenological and yield related traits at three locations in Pakistan under normal sowing time and late sowing time for expose to prolonged high temperature. With the help of genome-wide association study using genotyping-by-sequencing, marker trait associations (MTAs) were observed separately for the traits under normal and late sown conditions. RESULTS: Significant reduction ranging from 9 to 74% was observed in all traits under high temperature. Especially 30, 25, 41 and 66% reduction was observed for days to heading (DH), plant height (PH), spikes per plant (SPP) and yield respectively. We identified 55,954 single nucleotide polymorphisms (SNPs) using genotyping by sequencing of these 125 hexaploid spring wheat genotypes and conducted genome-wide association studies (GWAS) for days to heading (DH), grain filled duration (GFD), plant height (PH), spikes per plant (SPP), grain number per spike (GNS), thousand kernel weight (TKW) and grain yield per plot (GY). Genomic regions identified through GWAS explained up to 13% of the phenotypic variance, on average. A total of 139 marker-trait associations (MTAs) across three wheat genomes (56 on genome A, 55 on B and 28 on D) were identified for all the seven traits studied. For days to heading, 20; grain filled duration, 21; plant height, 23; spikes per plant, 13; grain numbers per spike, 8; thousand kernel weight, 21 and for grain yield, 33 MTAs were detected under normal and late sown conditions. CONCLUSIONS: This study identifies the essential resource of genetics research and underpins the chromosomal regions of seven agronomic traits under normal and high temperature. Significant relationship was observed between the number of favored alleles and trait observations. Fourteen protein coding genes with their respective annotations have been searched with the sequence of seven MTAs which were identified in this study. These findings will be helpful in the development of a breeder friendly platform for the selection of high yielding wheat lines at high temperature areas.


Assuntos
Agricultura , Genoma de Planta , Estudo de Associação Genômica Ampla , Característica Quantitativa Herdável , Triticum/genética , Alelos , Pão , Genes de Plantas , Marcadores Genéticos , Genótipo , Desequilíbrio de Ligação/genética , Fenótipo , Mapeamento Físico do Cromossomo , Análise de Componente Principal
9.
BMC Plant Biol ; 19(1): 166, 2019 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-31029090

RESUMO

BACKGROUND: Plant breeding has been proposed as one of the most effective and environmentally safe methods to control fungal infection and to reduce fumonisin accumulation. However, conventional breeding can be hampered by the complex genetic architecture of resistance to fumonisin accumulation and marker-assisted selection is proposed as an efficient alternative. In the current study, GWAS has been performed for the first time for detecting high-resolution QTL for resistance to fumonisin accumulation in maize kernels complementing published GWAS results for Fusarium ear rot. RESULTS: Thirty-nine SNPs significantly associated with resistance to fumonisin accumulation in maize kernels were found and clustered into 17 QTL. Novel QTLs for fumonisin content would be at bins 3.02, 5.02, 7.05 and 8.07. Genes with annotated functions probably implicated in resistance to pathogens based on previous studies have been highlighted. CONCLUSIONS: Breeding approaches to fix favorable functional variants for genes implicated in maize immune response signaling may be especially useful to reduce kernel contamination with fumonisins without significantly interfering in mycelia development and growth and, consequently, in the beneficial endophytic behavior of Fusarium verticillioides.


Assuntos
Fumonisinas/metabolismo , Genoma de Planta , Estudo de Associação Genômica Ampla , Sementes/metabolismo , Zea mays/genética , Zea mays/metabolismo , Endogamia , Modelos Lineares , Desequilíbrio de Ligação/genética , Polimorfismo de Nucleotídeo Único/genética
10.
Nat Commun ; 10(1): 1776, 2019 04 16.
Artigo em Inglês | MEDLINE | ID: mdl-30992449

RESUMO

Polygenic risk scores (PRS) have shown promise in predicting human complex traits and diseases. Here, we present PRS-CS, a polygenic prediction method that infers posterior effect sizes of single nucleotide polymorphisms (SNPs) using genome-wide association summary statistics and an external linkage disequilibrium (LD) reference panel. PRS-CS utilizes a high-dimensional Bayesian regression framework, and is distinct from previous work by placing a continuous shrinkage (CS) prior on SNP effect sizes, which is robust to varying genetic architectures, provides substantial computational advantages, and enables multivariate modeling of local LD patterns. Simulation studies using data from the UK Biobank show that PRS-CS outperforms existing methods across a wide range of genetic architectures, especially when the training sample size is large. We apply PRS-CS to predict six common complex diseases and six quantitative traits in the Partners HealthCare Biobank, and further demonstrate the improvement of PRS-CS in prediction accuracy over alternative methods.


Assuntos
Predisposição Genética para Doença , Modelos Genéticos , Herança Multifatorial/genética , Característica Quantitativa Herdável , Artrite Reumatoide/diagnóstico , Artrite Reumatoide/genética , Teorema de Bayes , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Simulação por Computador , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/genética , Bases de Dados Genéticas/estatística & dados numéricos , Depressão/diagnóstico , Depressão/genética , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/genética , Feminino , Estudo de Associação Genômica Ampla , Humanos , Doenças Inflamatórias Intestinais/diagnóstico , Doenças Inflamatórias Intestinais/genética , Desequilíbrio de Ligação/genética , Masculino , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco
11.
BMC Plant Biol ; 19(1): 95, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30841851

RESUMO

BACKGROUND: Seeds of domesticated barley are grouped into two distinct types, which differ in morphology. Caryopses covered by adaxial (palea) and abaxial (lemma) hulls that tightly adhere to the pericarp at maturity give rise to hulled seeds whereas caryopses without adhering hulls give rise to naked seeds. The naked caryopsis character is an essential trait regarding the end use of barley. RESULTS: To uncover the genetic basis of the trait, a genome-wide association study (GWAS) has been performed in a panel comprising 222 2-rowed and 303 6-rowed spring barley landrace accessions. In addition to the well-described Nud locus on chromosome 7H, three novel loci showed strong associations with the trait: the first locus on 2H was specifically detected in 6-rowed accessions, the second locus on 3H was found in 2-rowed accessions from Eurasia and the third locus on 6H was revealed in 6-rowed accessions from Ethiopia. PCR analysis of naked accessions also confirmed the absence of a 17 kb region harboring the Nud gene on chromosome 7H for all but one naked accession. The latter was characterized by a slightly variant phenotype of the caryopsis. CONCLUSION: Our findings provide evidence of the pervasiveness of the 17 kb deletion in spring barley from different geographic regions and at the same time reveal genomic footprints of selection in naked barley, which follow both geographic and morphological patterns.


Assuntos
Estudo de Associação Genômica Ampla/métodos , Hordeum/genética , Sementes/genética , Desequilíbrio de Ligação/genética , Locos de Características Quantitativas/genética
12.
PLoS Biol ; 17(2): e3000071, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30818353

RESUMO

Information on crop pedigrees can be used to help maximise genetic gain in crop breeding and allow efficient management of genetic resources. We present a pedigree resource of 2,657 wheat (Triticum aestivum L.) genotypes originating from 38 countries, representing more than a century of breeding and variety development. Visualisation of the pedigree enables illustration of the key developments in United Kingdom wheat breeding, highlights the wide genetic background of the UK wheat gene pool, and facilitates tracing the origin of beneficial alleles. A relatively high correlation between pedigree- and marker-based kinship coefficients was found, which validated the pedigree and enabled identification of errors in the pedigree or marker data. Using simulations with a combination of pedigree and genotype data, we found evidence for significant effects of selection by breeders. Within crosses, genotypes are often more closely related than expected by simulations to one of the parents, which indicates selection for favourable alleles during the breeding process. Selection across the pedigree was demonstrated on a subset of the pedigree in which 110 genotyped varieties released before the year 2000 were used to simulate the distribution of marker alleles of 45 genotyped varieties released after the year 2000, in the absence of selection. Allelic diversity in the 45 varieties was found to deviate significantly from the simulated distributions at a number of loci, indicating regions under selection over this period. The identification of one of these regions as coinciding with a strong yield component quantitative trait locus (QTL) highlights both the potential of the remaining loci as wheat breeding targets for further investigation, as well as the utility of this pedigree-based methodology to identify important breeding targets in other crops. Further evidence for selection was found as greater linkage disequilibrium (LD) for observed versus simulated genotypes within all chromosomes. This difference was greater at shorter genetic distances, indicating that breeder selections have conserved beneficial linkage blocks. Collectively, this work highlights the benefits of generating detailed pedigree resources for crop species. The wheat pedigree database developed here represents a valuable community resource and will be updated as new varieties are released at https://www.niab.com/pages/id/501/UK_Wheat_varieties_Pedigree.


Assuntos
Adaptação Fisiológica , Cruzamento , Triticum/fisiologia , Alelos , Cromossomos de Plantas/genética , Ligação Genética , Marcadores Genéticos , Genoma de Planta , Genótipo , Desequilíbrio de Ligação/genética , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Triticum/genética
13.
Nat Genet ; 51(4): 675-682, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30926970

RESUMO

Transcriptome-wide association studies using predicted expression have identified thousands of genes whose locally regulated expression is associated with complex traits and diseases. In this work, we show that linkage disequilibrium induces significant gene-trait associations at non-causal genes as a function of the expression quantitative trait loci weights used in expression prediction. We introduce a probabilistic framework that models correlation among transcriptome-wide association study signals to assign a probability for every gene in the risk region to explain the observed association signal. Importantly, our approach remains accurate when expression data for causal genes are not available in the causal tissue by leveraging expression prediction from other tissues. Our approach yields credible sets of genes containing the causal gene at a nominal confidence level (for example, 90%) that can be used to prioritize genes for functional assays. We illustrate our approach by using an integrative analysis of lipid traits, where our approach prioritizes genes with strong evidence for causality.


Assuntos
Predisposição Genética para Doença/genética , Transcriptoma/genética , Mapeamento Cromossômico/métodos , Estudo de Associação Genômica Ampla/métodos , Humanos , Desequilíbrio de Ligação/genética , Modelos Genéticos , Fenótipo , Polimorfismo de Nucleotídeo Único/genética , Probabilidade , Locos de Características Quantitativas/genética
14.
Nat Genet ; 51(4): 683-693, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30858613

RESUMO

Widespread linkage disequilibrium and incomplete annotation of cell-to-cell state variation represent substantial challenges to elucidating mechanisms of trait-associated genetic variation. Here we perform genetic fine-mapping for blood cell traits in the UK Biobank to identify putative causal variants. These variants are enriched in genes encoding proteins in trait-relevant biological pathways and in accessible chromatin of hematopoietic progenitors. For regulatory variants, we explore patterns of developmental enhancer activity, predict molecular mechanisms, and identify likely target genes. In several instances, we localize multiple independent variants to the same regulatory element or gene. We further observe that variants with pleiotropic effects preferentially act in common progenitor populations to direct the production of distinct lineages. Finally, we leverage fine-mapped variants in conjunction with continuous epigenomic annotations to identify trait-cell type enrichments within closely related populations and in single cells. Our study provides a comprehensive framework for single-variant and single-cell analyses of genetic associations.


Assuntos
Hematopoese/genética , Polimorfismo de Nucleotídeo Único/genética , Linhagem da Célula/genética , Cromatina/genética , Mapeamento Cromossômico/métodos , Epigenômica/métodos , Estudo de Associação Genômica Ampla/métodos , Humanos , Desequilíbrio de Ligação/genética , Fenótipo , Locos de Características Quantitativas/genética , Sequências Reguladoras de Ácido Nucleico/genética
15.
Int J Mol Sci ; 20(6)2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30897750

RESUMO

Prion disease has displayed large infection host ranges among several species; however, dogs have not been reported to be infected and are considered prion disease-resistant animals. Case-controlled studies in several species, including humans and cattle, indicated a potent association of prion protein gene (PRNP) polymorphisms in the progression of prion disease. Thus, because of the proximal location and similar structure of the PRNP gene among the prion gene family, the prion-like protein gene (PRND) was noted as a novel candidate gene that contributes to prion disease susceptibility. Several case-controlled studies have confirmed the relationship of the PRND gene with prion disease vulnerability, and strong genetic linkage disequilibrium blocks were identified in prion-susceptible species between the PRNP and PRND genes. However, to date, polymorphisms of the dog PRND gene have not been reported, and the genetic linkage between the PRNP and PRND genes has not been examined thus far. Here, we first investigated dog PRND polymorphisms in 207 dog DNA samples using direct DNA sequencing. A total of four novel single nucleotide polymorphisms (SNPs), including one nonsynonymous SNP (c.149G>A, R50H), were identified in this study. We also found two major haplotypes among the four novel SNPs. In addition, we compared the genotype and allele frequencies of the c.149G>A (R50H) SNP and found significantly different distributions among eight dog breeds. Furthermore, we annotated the c.149G>A (R50H) SNP of the dog PRND gene using in silico tools, PolyPhen-2, PROVEAN, and PANTHER. Finally, we examined linkage disequilibrium between the PRNP and PRND genes in dogs. Interestingly, we did not find a strong genetic linkage between these two genes. To the best of our knowledge, this was the first genetic study of the PRND gene in a prion disease-resistant animal, a dog.


Assuntos
Doenças Priônicas/genética , Animais , Estudos de Casos e Controles , Cães , Frequência do Gene/genética , Ligação Genética/genética , Predisposição Genética para Doença/genética , Genótipo , Haplótipos/genética , Desequilíbrio de Ligação/genética , Proteínas Priônicas/genética , Príons
16.
Nat Genet ; 51(4): 636-648, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30926973

RESUMO

The concentrations of high- and low-density-lipoprotein cholesterol and triglycerides are influenced by smoking, but it is unknown whether genetic associations with lipids may be modified by smoking. We conducted a multi-ancestry genome-wide gene-smoking interaction study in 133,805 individuals with follow-up in an additional 253,467 individuals. Combined meta-analyses identified 13 new loci associated with lipids, some of which were detected only because association differed by smoking status. Additionally, we demonstrate the importance of including diverse populations, particularly in studies of interactions with lifestyle factors, where genomic and lifestyle differences by ancestry may contribute to novel findings.


Assuntos
Lipídeos/sangue , Lipídeos/genética , Fumar/sangue , Fumar/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Estudo de Associação Genômica Ampla/métodos , Genótipo , Humanos , Estilo de Vida , Desequilíbrio de Ligação/genética , Masculino , Pessoa de Meia-Idade , Adulto Jovem
17.
Gene ; 696: 186-196, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30790653

RESUMO

The COMT gene encodes for catechol-O-methyl-transferase, an enzyme playing a major role in regulation of synaptic catecholamine neurotransmitters. Investigating 4 markers of the COMT gene (rs2020917, rs4818, rs4680, rs9332377) in 6 Tunisian populations and a pool of Libyans. Our objective was to determine the distribution of allelic, genotypic and haplotypic frequencies by comparison to other populations of the 1000 genomes project and 59 populations from the Kidd Lab dataset. The allelic frequencies established for these SNPs in the North African populations are similar to those of Europeans and South Asians. Linkage disequilibrium between these SNPs and haplotypes frequencies are different between populations whose clustering in principal components analysis (PCA) according to their geographic origin was more significant using haplotypic frequencies. COMT activity prediction by haplotypes genotyping could be limited to rs4818-rs4680 micro-haplotypes. The Low activity haplotype (CG) displays the highest frequency in African populations (55%), in the 59 Kidd Lab populations we found also that Sub-Saharan Africans, Native Americans, and some East Asian and Pacific Island populations all have frequencies in the 50-81% range for (CG) where as its lowest frequency was found in Europeans (10%), this results have been also confirmed for Southwest Asians. North Africans and South Asians with intermediate frequencies have approximately similar values (20% and 25%). Europeans show the highest frequencies of haplotypes with predicted High and Medium activity in contrast to Africans. North Africans and South Asians present similar results for all the category of the COMT activity prediction by haplotypes genotyping. The high level of genetic diversity of COMT haplotypes, not only allows distinction between populations according to their history settlement, origin and ethnicity, it constitutes a basis for studies of association of the COMT gene polymorphism with pathologies, drugs response and for forensic investigation in North African populations.


Assuntos
Grupo com Ancestrais do Continente Africano/genética , Catecol O-Metiltransferase/genética , Frequência do Gene/genética , Desequilíbrio de Ligação/genética , Polimorfismo de Nucleotídeo Único/genética , Aclimatação/genética , África do Norte , Alelos , Catecol O-Metiltransferase/metabolismo , Genética Forense/métodos , Haplótipos/genética , Voluntários Saudáveis , Humanos , Farmacogenética/métodos
18.
Leg Med (Tokyo) ; 37: 64-66, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30711876

RESUMO

We presented allele frequencies of 27 X-chromosomal short tandem repeats (DXS6807, DXS9902, DXS6795, DXS6810, DXS10076, DXS10077, DXS10078, DXS10162, DXS10163, DXS10164, DXS7132, DXS981, DXS6800, DXS6803, DXS6809, DXS6789, DXS6799, DXS7424, DXS101, DXS7133, GATA172D05, DXS10103, HPRTB, GATA31E08, DXS8377, DXS10147, and DXS7423) obtained from 352 unrelated individuals in Egypt. No deviation from Hardy-Weinberg equilibrium was detected. Two pairs of adjacent loci showed significant linkage disequilibrium. In the principal component analysis plot, the Egyptian data were located between Europe and sub-Saharan Africa, away from Asia.


Assuntos
Cromossomos Humanos X/genética , Frequência do Gene/genética , Repetições de Microssatélites/genética , Polimorfismo Genético/genética , Egito , Feminino , Loci Gênicos/genética , Humanos , Desequilíbrio de Ligação/genética , Masculino
19.
Nat Genet ; 51(3): 379-386, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30718926

RESUMO

To understand the genetics of type 2 diabetes in people of Japanese ancestry, we conducted A meta-analysis of four genome-wide association studies (GWAS; 36,614 cases and 155,150 controls of Japanese ancestry). We identified 88 type 2 diabetes-associated loci (P < 5.0 × 10-8) with 115 independent signals (P < 5.0 × 10-6), of which 28 loci with 30 signals were novel. Twenty-eight missense variants were in linkage disequilibrium (r2 > 0.6) with the lead variants. Among the 28 missense variants, three previously unreported variants had distinct minor allele frequency (MAF) spectra between people of Japanese and European ancestry (MAFJPN > 0.05 versus MAFEUR < 0.01), including missense variants in genes related to pancreatic acinar cells (GP2) and insulin secretion (GLP1R). Transethnic comparisons of the molecular pathways identified from the GWAS results highlight both ethnically shared and heterogeneous effects of a series of pathways on type 2 diabetes (for example, monogenic diabetes and beta cells).


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Diabetes Mellitus Tipo 2/genética , Loci Gênicos/genética , Predisposição Genética para Doença/genética , Adulto , Estudos de Casos e Controles , Grupo com Ancestrais do Continente Europeu/genética , Feminino , Frequência do Gene/genética , Estudo de Associação Genômica Ampla/métodos , Genótipo , Humanos , Desequilíbrio de Ligação/genética , Masculino , Polimorfismo de Nucleotídeo Único/genética
20.
Int J Mol Sci ; 20(3)2019 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-30759829

RESUMO

Tibetan wild barley has been identified to show large genetic variation and stress tolerance. A genome-wide association (GWA) analysis was performed to detect quantitative trait loci (QTLs) for drought tolerance using 777 Diversity Array Technology (DArT) markers and morphological and physiological traits of 166 Tibetan wild barley accessions in both hydroponic and pot experiments. Large genotypic variation for these traits was found; and population structure and kinship analysis identified three subpopulations among these barley genotypes. The average LD (linkage disequilibrium) decay distance was 5.16 cM, with the minimum on 6H (0.03 cM) and the maximum on 4H (23.48 cM). A total of 91 DArT markers were identified to be associated with drought tolerance-related traits, with 33, 26, 16, 1, 3, and 12 associations for morphological traits, H⁺K⁺-ATPase activity, antioxidant enzyme activities, malondialdehyde (MDA) content, soluble protein content, and potassium concentration, respectively. Furthermore, 7 and 24 putative candidate genes were identified based on the reference Meta-QTL map and by searching the Barleymap. The present study implicated that Tibetan annual wild barley from Qinghai⁻Tibet Plateau is rich in genetic variation for drought stress. The QTLs detected by genome-wide association analysis could be used in marker-assisting breeding for drought-tolerant barley genotypes and provide useful information for discovery and functional analysis of key genes in the future.


Assuntos
Hordeum/genética , Locos de Características Quantitativas/genética , Estresse Fisiológico/genética , Adaptação Fisiológica/genética , Biomarcadores/metabolismo , Secas , Variação Genética/genética , Estudo de Associação Genômica Ampla/métodos , Genótipo , Desequilíbrio de Ligação/genética , Fenótipo , Melhoramento Vegetal/métodos , Tibet
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