QTL data extraction and colocalization • catalogueR

Rapid querying, colocalization, and plotting of summary stats from the eQTL Catalogue.

eQTL Catalogue currently contains 110 QTL datasets (full, genome-wide, standardized summary statistics and metadata) from 20 different studies (including GTEx V8), across many tissues/cell types/conditions (updated: 7/5/20).

Intro

The functions in catalogueR are partly derived from the eQTL Catalogue tutorial.
Additional eQTL Catalogue resources:

GitHub repository
In-depth API documentation
Preprint
FTP server: ftp://ftp.ebi.ac.uk/pub/databases/spot/eQTL/csv

NOTE: The ALT allele is always the effect allele in eQTL Catalogue.

Documentation

Website

PDF

Getting started

Installation

[1] Optional step: conda

To ensure all dependendencies are installed and don’t conflict with each other, you can create a conda environment by downloading this yaml` file and entering the following in command line:

conda env create -n <path_to_yml>/catalogueR.yml

[2] Install catalogueR in R

If you don’t use the conda env, you will also need to make sure tabix is installed.

tabix (Install via conda or from source)

if(!"devtools" %in% installed.packages()){install.packages("devtools")}
devtools::install_github("RajLabMSSM/catalogueR")

Intro example

Supply one or more paths to [GWAS] summary stats files (one per locus) and automatically download any eQTL data within that range. The files can be any of these formats, either gzip-compressed (.gz) or uncompressed: .csv, .tsv, space-separated

The summary stats files must have the following column names (order doesn’t matter):

SNP (rsid for each SNP)
CHR (chromosome; with or without the “chr” prefix is fine)
POS (basepair position)
… (optional extra columns)

sumstats_paths <- example_sumstats_paths()

gwas.qtl_paths <- eQTL_Catalogue.query(sumstats_paths = sumstats_paths,  
                                       qtl_search = c("myeloid","Alasoo_2018"),
                                       output_dir = "./catalogueR_queries", 
                                       split_files = T,  
                                       merge_with_gwas = T,
                                       force_new_subset = T,
                                       nThread=4)
GWAS.QTL <- gather_files(file_paths = gwas.qtl_paths)
# Interactive datatable of results 
## WARNING: Don't use this function on large datatables, might cause freezing.
createDT(head(GWAS.QTL))

Author

Brian M. Schilder
Raj Lab
Icahn School of Medicine at Mount Sinai
New York, New York, USA

catalogueR