scholarly journals A Genome-Wide Association Analysis Reveals Epistatic Cancellation of Additive Genetic Variance for Root Length in Arabidopsis thaliana

PLoS Genetics ◽  
2015 ◽  
Vol 11 (9) ◽  
pp. e1005541 ◽  
Author(s):  
Jennifer Lachowiec ◽  
Xia Shen ◽  
Christine Queitsch ◽  
Örjan Carlborg
2014 ◽  
Author(s):  
Jennifer Lachowiec ◽  
Xia Shen ◽  
Christine Queitsch ◽  
Örjan Carlborg

Efforts to identify loci underlying complex traits generally assume that most genetic variance is additive. Here, we examined the genetics of Arabidopsis thaliana root length and found that the narrow-sense heritability for this trait was statistically zero. This low additive genetic variance likely explains why no associations to root length could be found using standard additive-model-based genome-wide association (GWA) approaches. However, the broad-sense heritability for root length was significantly larger, and we therefore also performed an epistatic GWA analysis to map loci contributing to the epistatic genetic variance. This analysis revealed four interacting pairs involving seven chromosomal loci that passed a standard multiple-testing corrected significance threshold. Explorations of the genotype-phenotype maps for these pairs revealed that the detected epistasis cancelled out the additive genetic variance, explaining why these loci were not detected in the additive GWA analysis. Small population sizes, such as in our experiment, increase the risk of identifying false epistatic interactions due to testing for associations with very large numbers of multi-marker genotypes in few phenotyped individuals. Therefore, we estimated the false-positive risk using a new statistical approach that suggested half of the associated pairs to be true positive associations. Our experimental evaluation of candidate genes within the seven associated loci suggests that this estimate is conservative; we identified functional candidate genes that affected root development in four loci that were part of three of the pairs. In summary, statistical epistatic analyses were found to be indispensable for confirming known, and identifying several new, functional candidate genes for root length using a population of wild-collected A. thaliana accessions. We also illustrated how epistatic cancellation of the additive genetic variance resulted in an insignificant narrow-sense, but significant broad-sense heritability that could be dissected into the contributions of several individual loci using a combination of careful statistical epistatic analyses and functional genetic experiments.


2020 ◽  
Vol 103 (12) ◽  
pp. 11605-11617
Author(s):  
Maria Gracia Luigi-Sierra ◽  
Vincenzo Landi ◽  
Dailu Guan ◽  
Juan Vicente Delgado ◽  
Anna Castelló ◽  
...  

2016 ◽  
Vol 177 ◽  
pp. 31-40.e6 ◽  
Author(s):  
Joon Seol Bae ◽  
InSong Koh ◽  
Hyun Sub Cheong ◽  
Jeong-Meen Seo ◽  
Dae-Yeon Kim ◽  
...  

animal ◽  
2016 ◽  
Vol 10 (10) ◽  
pp. 1602-1608 ◽  
Author(s):  
H.Y. Ji ◽  
B. Yang ◽  
Z.Y. Zhang ◽  
J. Ouyang ◽  
M. Yang ◽  
...  

Author(s):  
David Ellinghaus ◽  
Frauke Degenhardt ◽  
Luis Bujanda ◽  
Maria Buti ◽  
Agustín Albillos ◽  
...  

ABSTRACTBackgroundRespiratory failure is a key feature of severe Covid-19 and a critical driver of mortality, but for reasons poorly defined affects less than 10% of SARS-CoV-2 infected patients.MethodsWe included 1,980 patients with Covid-19 respiratory failure at seven centers in the Italian and Spanish epicenters of the SARS-CoV-2 pandemic in Europe (Milan, Monza, Madrid, San Sebastian and Barcelona) for a genome-wide association analysis. After quality control and exclusion of population outliers, 835 patients and 1,255 population-derived controls from Italy, and 775 patients and 950 controls from Spain were included in the final analysis. In total we analyzed 8,582,968 single-nucleotide polymorphisms (SNPs) and conducted a meta-analysis of both case-control panels.ResultsWe detected cross-replicating associations with rs11385942 at chromosome 3p21.31 and rs657152 at 9q34, which were genome-wide significant (P<5×10−8) in the meta-analysis of both study panels, odds ratio [OR], 1.77; 95% confidence interval [CI], 1.48 to 2.11; P=1.14×10−10 and OR 1.32 (95% CI, 1.20 to 1.47; P=4.95×10−8), respectively. Among six genes at 3p21.31, SLC6A20 encodes a known interaction partner with angiotensin converting enzyme 2 (ACE2). The association signal at 9q34 was located at the ABO blood group locus and a blood-group-specific analysis showed higher risk for A-positive individuals (OR=1.45, 95% CI, 1.20 to 1.75, P=1.48×10−4) and a protective effect for blood group O (OR=0.65, 95% CI, 0.53 to 0.79, P=1.06×10−5).ConclusionsWe herein report the first robust genetic susceptibility loci for the development of respiratory failure in Covid-19. Identified variants may help guide targeted exploration of severe Covid-19 pathophysiology.


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