scholarly journals High density genome wide genotyping-by-sequencing and association identifies common and low frequency SNPs, and novel candidate genes influencing cow milk traits

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Eveline M. Ibeagha-Awemu ◽  
Sunday O. Peters ◽  
Kingsley A. Akwanji ◽  
Ikhide G. Imumorin ◽  
Xin Zhao

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Guosong Zhang ◽  
Jie Li ◽  
Jiajia Zhang ◽  
Xia Liang ◽  
Tao Wang ◽  
...  

Abstract Background A high-density genetic linkage map is essential for QTL fine mapping, comparative genome analysis, identification of candidate genes and marker-assisted selection in aquaculture species. Pelteobagrus vachelli is a very popular commercial species in Asia. However, some specific characters hindered achievement of the traditional selective breeding based on phenotypes, such as lack of large-scale genomic resource and short of markers tightly associated with growth, sex determination and hypoxia tolerance related traits. Results By making use of 5059 ddRAD markers in P. vachelli, a high-resolution genetic linkage map was successfully constructed. The map’ length was 4047.01 cM by using an interval of 0.11 cm, which is an average marker standard. Comparative genome mapping revealed that a high proportion (83.2%) of markers with a one-to-one correspondence were observed between P. vachelli and P. fulvidraco. Based on the genetic map, 8 significant genome-wide QTLs for 4 weight, 1 body proportion, 2 sex determination, and 1 hypoxia tolerance related traits were detected on 4 LGs. Some SNPs from these significant genome-wide QTLs were observably associated with these phenotypic traits in other individuals by Kompetitive Allele Specific PCR. In addition, two candidate genes for weight, Sipa1 and HSD11B2, were differentially expressed between fast-, medium- and slow-growing P. vachelli. Sema7a, associated with hypoxia tolerance, was induced after hypoxia exposure and reoxygenation. Conclusions We mapped a set of suggestive and significant QTLs as well as candidate genes for 12 growth, 1 sex determination and 1 hypoxia tolerance related traits based on a high-density genetic linkage map by making use of SNP markers for P. fulvidraco. Our results have offered a valuable method about the much more efficient production of all-male, fast growth and hypoxia tolerance P. vachelli for the aquaculture industry.



2019 ◽  
Author(s):  
Jaime Osorio ◽  
Gina Garzón ◽  
Paola Delgadillo ◽  
Silvio Bastidas ◽  
Leidy Moreno ◽  
...  

Abstract Background The genus Elaeis has two species of economic importance for the oil palm agroindustry: Elaeis oleifera (O), native to the Americas, and Elaeis guineensis (G), native to Africa. This work provides to our knowledge, the first association mapping study in an interspecific OxG oil palm population, which shows tolerance to pests and diseases, high oil quality, and acceptable fruit bunch production. Results Using genotyping-by-sequencing (GBS), we identified a total of 3,776 single nucleotide polymorphisms (SNPs) that were used to perform a genome-wide association analysis (GWAS) in 378 OxG hybrid population for 10 agronomic traits. Twelve genomic regions (SNPs) were located near candidate genes implicated in multiple functional categories, such as tissue growth, cellular trafficking, and physiological processes. Conclusions We provide new insights on genomic regions that mapped on candidate genes involved in plant architecture and yield. These potential candidate genes need to be confirmed for future targeted functional analyses. Associated markers to the traits of interest may be valuable resources for the development of marker-assisted selection in oil palm breeding. Keywords: Association mapping, Elaeis guineensis , Elaeis oleifera , genotyping-by-sequencing, plant architecture, yield.



2018 ◽  
Author(s):  
Anubha Mahajan ◽  
Daniel Taliun ◽  
Matthias Thurner ◽  
Neil R Robertson ◽  
Jason M Torres ◽  
...  

We aggregated genome-wide genotyping data from 32 European-descent GWAS (74,124 T2D cases, 824,006 controls) imputed to high-density reference panels of >30,000 sequenced haplotypes. Analysis of ˜27M variants (˜21M with minor allele frequency [MAF]<5%), identified 243 genome-wide significant loci (p<5×10−8; MAF 0.02%-50%; odds ratio [OR] 1.04-8.05), 135 not previously-implicated in T2D-predisposition. Conditional analyses revealed 160 additional distinct association signals (p<10−5) within the identified loci. The combined set of 403 T2D-risk signals includes 56 low-frequency (0.5%≤MAF<5%) and 24 rare (MAF<0.5%) index SNPs at 60 loci, including 14 with estimated allelic OR>2. Forty-one of the signals displayed effect-size heterogeneity between BMI-unadjusted and adjusted analyses. Increased sample size and improved imputation led to substantially more precise localisation of causal variants than previously attained: at 51 signals, the lead variant after fine-mapping accounted for >80% posterior probability of association (PPA) and at 18 of these, PPA exceeded 99%. Integration with islet regulatory annotations enriched for T2D association further reduced median credible set size (from 42 variants to 32) and extended the number of index variants with PPA>80% to 73. Although most signals mapped to regulatory sequence, we identified 18 genes as human validated therapeutic targets through coding variants that are causal for disease. Genome wide chip heritability accounted for 18% of T2D-risk, and individuals in the 2.5% extremes of a polygenic risk score generated from the GWAS data differed >9-fold in risk. Our observations highlight how increases in sample size and variant diversity deliver enhanced discovery and single-variant resolution of causal T2D-risk alleles, and the consequent impact on mechanistic insights and clinical translation.



Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 418
Author(s):  
Fan Shao ◽  
Jing Liu ◽  
Mengyuan Ren ◽  
Junying Li ◽  
Haigang Bao ◽  
...  

Dwarfism is a condition defined by low harvest weight in fish, but also results in strange body figures which may have potential for the selective breeding of new ornamental fish strains. The objectives of this study are to reveal the physiological causes of dwarfism and identify the genetic loci controlling this trait in the white sailfin molly. Skeletons of dwarf and normal sailfin mollies were observed by X-ray radioscopy and skeletal staining. Genome-wide association studies based on genotyping-by-sequencing (n = 184) were used to map candidate genomic regions associated with the dwarfism trait. Quantitative real-time PCR was performed to determine the expression level of candidate genes in normal (n = 8) and dwarf (n = 8) sailfin mollies. We found that the dwarf sailfin molly has a short and dysplastic spine in comparison to the normal fish. Two regions, located at NW_015112742.1 and NW_015113621.1, were significantly associated with the dwarfism trait. The expression level of three candidate genes, ADAMTS like 1, Larp7 and PPP3CA, were significantly different between the dwarf and normal sailfin mollies in the hepatopancreas, with PPP3CA also showing significant differences in the vertebrae and Larp7 showing significant differences in the muscle. This study identified genomic regions and candidate genes associated with the dwarfism trait in the white sailfin molly and would provide a reference to determine dwarf-causing variations.



2019 ◽  
Author(s):  
Deissy Katherine Juyo Rojas ◽  
Johana Carolina Soto Sedano ◽  
Agim Ballvora ◽  
Jens Léon ◽  
Teresa Mosquera Vásquez

AbstractPotato, Solanum tuberosum, is one of the highest consumed food in the world, being the basis of the diet of millions of people. The main limiting and destructive disease of potato is late blight, caused by Phytophtora infestans. Here, we present a multi-environmental analysis of the response to P. infestans using an association panel of 150 accessions of S. tuberosum Group Phureja, evaluated in two localities in Colombia. Disease resistance data were merged with a genotyping matrix of 83,862 SNPs obtained by 2b-restriction site–associated DNA and Genotyping by sequencing approaches into a Genome-wide association study. We are reporting 16 organ-specific QTL conferring resistance to late blight. These QTL explain from 13.7% to 50.9% of the phenotypic variance. Six and ten QTL were detected for resistance response in leaves and stem, respectively. In silico analysis revealed 15 candidate genes for resistance to late blight. Four of them have no functional genome annotation, while eleven candidate genes code for diverse proteins, including one leucine-rich repeat kinase.



2019 ◽  
Author(s):  
Jaime Osorio ◽  
Gina Garzón ◽  
Paola Delgadillo ◽  
Silvio Bastidas ◽  
Leidy Moreno ◽  
...  

Abstract Abstract Background The genus Elaeis has two species of economic importance for the oil palm agroindustry: Elaeis oleifera (O), native to the Americas, and Elaeis guineensis (G), native to Africa. The work presented herein provides, to our knowledge, the first association mapping study in an interspecific OxG hybrid population of oil palm which presents tolerance to pests and diseases, high oil quality, and acceptable fruit bunch production. Results Using genotyping-by-sequencing (GBS), we identified a total of 3,776 single nucleotide polymorphisms (SNPs) that were used to perform a genome-wide association analysis (GWAS) in 378 OxG hybrids for 10 agronomic traits. Twelve genomic regions were located near candidate genes implicated in multiple functional categories, such as tissue growth, cellular trafficking, and physiological processes. Conclusions We provide new insights on candidate genes that mapped on genomic regions involved in plant architecture and yield; however, these potential candidate genes need to be confirmed for future targeted functional analysis. The associated markers may be valuable resources for the development of marker-assisted selection in oil palm breeding. Keywords: Association mapping, Elaeis guineensis, Elaeis oleifera, genotyping-by-sequencing, plant architecture, yield.



2019 ◽  
Author(s):  
Guosong Zhang ◽  
Jie Li ◽  
Jiajia Zhang ◽  
Xia Liang ◽  
Tao Wang ◽  
...  

Abstract Background: As is known to all, when we are doing QTL fine mapping, analyzing comparative genome, identifying candidate genes, making marker-assisted selection in aquaculture species, the high-density genetic linkage map is of great significance. Pelteobagrus vachelli is a very popular commercial species in Asia. However, some specific characters made it difficult to do traditional selective breeding based on phenotypes. For instance, potential problems include lacking in genomic resource which is in large scale and short of markers that is related tightly to growth, sex determination and hypoxia tolerance related traits. Results: By making use of 5059 ddRAD markers in P. vachelli,a high-resolution genetic linkage map was successfully constructed. The map’ length was 4047.01 cM by using an interval of 0.11 cm, which is an average marker standard. It is reflected that bu using comparative genome mapping, a large majority (83.2%) of markers with a one-to-one correspondence were observed between P. vachelli and P. fulvidraco. Based on the genetic map, 8 significant genome-wide QTLs for 4 weight, 1 body proportion, 2 sex determination, and 1 hypoxia tolerance related traits were detected on 4 LGs. Some SNPs from these significant genome-wide QTLs were observably associated with these phenotypic traits in other individuals by Kompetitive Allele Specific PCR. In addition, two candidate gene for weight, Sipa1 and HSD11B2, were differentially expressed between fast-, medium- and slow-growing P. vachelli. Sema7a, associated with hypoxia tolerance, was induced after hypoxia exposure and reoxygenation. Conclusions: We mapped a set of suggestive and significant QTLs as well as candidate genes for 12 growth, 1 sex determination and 1 hypoxia tolerance related traits based on a high-density genetic linkage map by making use of SNP markers for P. fulvidraco. Our results have offered a valuable method about the much more efficient production of all-male, fast growth and hypoxia tolerance P. vachelli for the aquaculture industry.



2019 ◽  
Author(s):  
Jaime Osorio ◽  
Gina Garzón ◽  
Paola Delgadillo ◽  
Silvio Bastidas ◽  
Leidy Moreno ◽  
...  

Abstract Background The genus Elaeis has two species of economic importance for the oil palm agroindustry: Elaeis oleifera (O), native to the Americas, and Elaeis guineensis (G), native to Africa. The breeding program in Colombia relies on interspecific OxG crossing populations with tolerance to pests and diseases, high oil quality, and acceptable fruit bunch production. The identification of loci associated to morphological and yield-related traits and the dissection of their genetic architecture will provide essential insights for oil palm breeding strategies. Results The genotypes of 471 oil palms, including 62 E. oleifera (O), 31 E. guineensis (G) and 378 OxG samples were analyzed in this study. A total of 3,776 single nucleotide polymorphisms (SNP) were detected across the 16 oil palm chromosomes using the genotyping-by-sequencing (GBS) technique. The genetic variation and population structure analyses grouped the samples into two clades according to the parental relatedness. A genome wide association analysis (GWAS) was conducting using the OxG hybrid population, resulting in 12 SNPs significantly associated with ten different morphological and yield-related traits. Conclusions The work presented herein provides to our knowledge the first association mapping study in an interspecific OxG hybrid population of oil palm. We provide new insights on candidate genes involved in tissue development and plant architecture associated to traits such as: rachis length, trunk diameter, bunch number, and bunch weight. The genes identified in our analysis are putative candidates for future targeted functional analysis. They are valuable resources for the development of marker-assisted selection in oil palm breeding. Keywords: Association mapping, Elaeis guineensis, Elaeis oleifera, genotyping-by-sequencing, plant architecture, yield.



2016 ◽  
Author(s):  
Dong Zhang ◽  
Nicholi J. Pitra ◽  
Mark C. Coles ◽  
Edward S. Buckler ◽  
Paul D. Matthews

AbstractGenome-wide meiotic recombination structures, sex chromosomes, and candidate genes for sex determination were discovered among Humulus spp. by application of a novel, high-density molecular marker system: ~1.2M single nucleotide polymorphisms (SNPs) were profiled with genotyping-by-sequencing (GBS) among 4512 worldwide accessions, including 4396 cultivars and landraces and 116 wild accessions of hops. Pre-qualified GBS markers were validated by inferences on families, population structures and phylogeny. Candidate genes discovered for several traits, including sex and drought stress-resistance, demonstrate the quality and utility of GBS SNPs for genome-wide association studies (GWAS) and Fst analysis in hops. Most importantly, pseudo-testcross mappings in F1 families delineated non-random linkage of Mendelian and non-Mendelian markers: structures that are indicative of unusual meiotic events which may have driven the evolution and cultivation of hops.



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