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| | == Lecture 2 == | | == Lecture 2 == |
| | | | |
| − | The slides describing the notes below are available [[Media:Stom practice 02.pdf | here (PDF)]]
| + | Please see [[Tutorial:_EMMAX_GotCloud_STOM:_Lecture_2]] |
| | | | |
| − | === Basic Setup === | + | == Lecture 5 == |
| | | | |
| − | * To see the files for the session, type
| + | Please see [[Tutorial:_EMMAX_GotCloud_STOM:_Lecture_5]] |
| − | ls /data/stom2014/session2/
| |
| − | If you see any errors, please let me know now!
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| | | | |
| − | * For convenience, let’s set some variables
| + | == Lecture 6 == |
| − | export S2=/data/stom2014/session2
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| − | mkdir ~/out
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| | | | |
| − | === Naive Association Test ===
| + | Please see [[Tutorial:_EMMAX_GotCloud_STOM:_Lecture_6]] |
| − | | |
| − | * Run naive association test using PLINK
| |
| − | | |
| − | $S2/bin/plink --noweb --bfile $S2/data/1000G.auto.omni.phased.EUR --pheno $S2/data/1000G_EUR_20_1459060.phe --linear --out ~/out/naive
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| − | | |
| − | * Check your output file and see what it looks like
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| − | | |
| − | less ~/out/naive.assoc.linear
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| − | | |
| − | * Check the p-value at the causal variant
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| − | | |
| − | grep -w ADD ~/out/naive.assoc.linear | grep 20:1459060
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| − | | |
| − | * Draw QQ plot using the following R commands
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| − | | |
| − | > source('/data/stom2014/session2/r/qqconf.r')
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| − | > T <- read.table('~/out/naive.assoc.linear',header=TRUE)
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| − | > pdf('~/out/naive.pdf')
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| − | > qq.conf.beta(T$P)
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| − | > dev.off()
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| − | | |
| − | === Genomic Control ===
| |
| − | | |
| − | * Add --adjust option to enable genomic control
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| − | | |
| − | $S2/bin/plink --noweb --bfile $S2/data/1000G.auto.omni.phased.EUR --pheno $S2/data/1000G_EUR_20_1459060.phe --linear --adjust --out ~/out/naive
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| − | | |
| − | * Calculate inflation factor on your own
| |
| − | | |
| − | > T <- read.table('~/out/naive.assoc.linear',header=TRUE)
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| − | | |
| − | ** First, find the median p-value
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| − | | |
| − | > median(T$P)
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| − | > 0.4814
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| − | | |
| − | ** Convert p-value into chi-square using R, and compute lambda
| |
| − | | |
| − | > qchisq(0.4814,1,lower.tail=FALSE)
| |
| − | [1] 0,4956901
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| − | > 0.4958032/0.456
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| − | [1] 1.08704
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| − | | |
| − | * Check out the custom script to calculate inflation factor
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| − | | |
| − | less $S2/r/calc.GC.lambda.r
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| − | | |
| − | ** Feed the p-values from association results
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| − | cut -c 96- ~/out/naive.assoc.linear | Rscript $S2/r/calc.GC.lambda.r
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| − | | |
| − | === Principal Component Analysis ===
| |
| − | | |
| − | * Convert PLINK format file to EMMAX-compatible format to obtain PCs
| |
| − | | |
| − | $S2/bin/plink --noweb --bfile $S2/data/1000G.auto.omni.phased.EUR --recode12 --output-missing-genotype 0 --transpose --out ~/out/1000G.auto.omni.phased.EUR
| |
| − | | |
| − | * Create kinship matrix using EMMAX
| |
| − | | |
| − | $S2/bin/emmax-kin-intel64 -T 1 -M 0.2 -v -d 10 ~/out/1000G.auto.omni.phased.EUR
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| − | less ~/out/1000G.auto.omni.phased.EUR.aBN.kinf
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| − | | |
| − | * Calculate principal component using custom script
| |
| − | | |
| − | Rscript $S2/r/calc.PC.from.kinf.r ~/out/1000G.auto.omni.phased.EUR.aBN.kinf ~/out/1000G.auto.omni.phased.EUR.tfam ~/out/1000G.auto.omni.phased.EUR.pc10
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| − | | |
| − | * Check out how the PCA outcome looks like
| |
| − | | |
| − | less ~/out/1000G.auto.omni.phased.EUR.pc10
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| − | | |
| − | * Visualize the population structure using PCs with custom script
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| − | | |
| − | Rscript $S2/r/plot_pc_pop.r ~/out/1000G.auto.omni.phased.EUR.pc10 $S2/data/1000G.auto.omni.phased.EUR.pop ~/out/1000G.auto.omni.phased.EUR.pc10.pdf
| |
| − | | |
| − | * Use PCs as covariates to adjust for PCs
| |
| − | | |
| − | $S2/bin/plink --noweb --bfile $S2/data/1000G.auto.omni.phased.EUR --pheno $S2/data/1000G_EUR_20_1459060.phe --covar ~/out/1000G.auto.omni.phased.EUR.pc10 --covar-number 1,2,3,4 --linear --adjust --out ~/out/pca
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| − | | |
| − | * Check out the p-value at the causal variant and inflation of statistics
| |
| − | | |
| − | grep -w ADD ~/out/pca.assoc.linear | grep 20:1459060
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| − | grep -w ADD ~/out/pca.assoc.linear | cut -c 96- | Rscript $S2/r/calc.GC.lambda.r
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| − | | |
| − | === Mixed Model Association ===
| |
| − | | |
| − | * Run EMMAX association
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| − | | |
| − | $S2/bin/emmax-intel64 -t ~/out/1000G.auto.omni.phased.EUR -o ~/out/emmax -p $S2/data/1000G_EUR_20_1459060.phe -k ~/out/1000G.auto.omni.phased.EUR.aBN.kinf
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| − | | |
| − | * Check the inflation factor
| |
| − | | |
| − | cut -f 4 ~out/emmax.ps | Rscript $S2/r/calc.GC.lambda.r
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| − | [1] 1.006079
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| − | | |
| − | * Draw and compare multiple QQ plots using the R function provided
| |
| − | | |
| − | > source('/data/stom2014/session2/r/qqconf.r')
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| − | > T1 <- read.table('~/out/naive.assoc.linear',header=TRUE)
| |
| − | > T2 <- read.table('~/out/pca.assoc.linear',header=TRUE)
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| − | > T3 <- read.table('~/out/emmax.ps')
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| − | > pdf('~/out/all.pdf')
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| − | > qq.conf.beta(T1$P)
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| − | > qq.conf.beta(T2$P,drawaxis=FALSE,ptcolor="blue")
| |
| − | > qq.conf.beta(T3$V4,drawaxis=FALSE,ptcolor="red")
| |
| − | > dev.off()
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