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Questions tagged [gwas]

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3 votes
1 answer
197 views

Estimating computing resources needed for a GWAS?

One of my dissertation papers is going to involve a GWAS. I have never actually run a GWAS before, and do not know how to estimate the computing resources I need for it. I asked someone on my ...
3 votes
1 answer
120 views

How to perform liftover from 38 to 37 in R?

I have some gwas summary statistics in GRCh38 that I want to lift to GRCh37. I am trying to liftover in R using this code: ...
2 votes
3 answers
314 views

How do I lift GWAS results to hg38?

There are some questions about lifting between reference builds, e.g. this one. But there doesn't appear to be a question about lifting a GWAS results file to a new reference build (except off-site). ...
1 vote
1 answer
286 views

LD clump GRCh38 GWAS results

The vignette of R package ieugwasr describes a plink based wrapper function for LD clumping GWAS data using the 1000 genomes ...
2 votes
1 answer
630 views

GWAS in python?

A question similar to this has also been asked on Biostars I understand GWAS is done with R, but are any written in Python? I'm used to python and java, acclimating to R will take a bit of time and my ...
3 votes
2 answers
99 views

Summary statistics version problem

I am learning GWAS study and PRS for predicting disease. I was aligning my sequencing data with GRCH38 reference panel. However, in the PRS analysis step, I found that most of the summary statistics ...
1 vote
0 answers
43 views

PLINK linear association testing command with an interaction and 2 covariates term

I am trying to write the right command for my association testing using PLINK 1.9 but I could not find a clear answer so far and not sure how to wrtie it correct. I have genotype variants called and ...
1 vote
2 answers
70 views

Why does my HWE QQ plot have extreme deviation and what does it mean?

This question was also asked on Reddit I have recently completed my thesis and one of the comments was that I report on why this graph looks this way. I have tried to find a reason but the closest I ...
5 votes
2 answers
3k views

What does PCA mean on GWAS

I understand what GWAS is and I'm able to perform certain tests with the p-values, etc. But what I am having a hard time wrapping my head around is what PCA on GWAS means. So let's say I have 100,000 ...
2 votes
2 answers
74 views

Loss of predictive power of polygenic risk score when dataset contains missing variants

I am trying to calculate polygenic risk scores (PRS) scores for a new dataset. This dataset does not have all the variants that the PRS score needs. The PRS score I am interested in has 40 variants, ...
4 votes
1 answer
177 views

How is the odds ratio of disease risk conferred by a 1-standard deviation increase in PRS calculated?

One standard deviation from the mean is commonly used to calculate a polygenic risk score for GWAS, e.g. human genetic disease. Why is this a common metric, for example why not 2-SD or 1.96 SD as in ...
2 votes
1 answer
97 views

How are the "effect_allele" and "other_allele" bases chosen in a PGS file from the PGS Catalog?

How are the "effect_allele" and "other_allele" bases chosen in a PGS file from the PGS Catalog? For example, for PGS002723 (https://www.pgscatalog.org/score/PGS002723/), if I set ...
1 vote
1 answer
145 views

Pandas automatically rounds GWAS P-value

I am working with a specific GWAS. If I were to run this on the command line grep <rs_id_of_interest> GWAS.txt I would see the GWAS p-value to be on the ...
2 votes
1 answer
522 views

Getting nearest gene from SNP data using SNP ID, CHR, and BP

I have data from a GWAS that provides me with the SNP, Chromosome, and base-pair. My data set has thousands of SNPs. What is the easiest way to find the nearest gene for each SNP using this ...
2 votes
2 answers
413 views

How to z-transform Fst and -log(p) values for genome wide selection scan?

I saw in the literature a lot genome wide scans showing $F_{ST}$ values in a 'z-transformed' format which seems to be bounded between 0 to infinity. Examples are found easily searching for 'genome-...

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