Calculate Fst to draw Manhattan plot
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4.1 years ago

Hi All,

I trying to calculate Fst. In the first step, I used the following script to calculate Fst with window 100 kb

./vcftools --vcf input_data.vcf --weir-fst-pop population_1.txt --weir-fst-pop population_2.txt --fst-window-size 100000 --fst-window-step 50000 --out pop1_vs_pop2

But in the next step, I do not know how to convert the output file to z-transform? Because before plotting the plot using the Manhattan package in R, z-transform must be performed.

Best Regard

Mostafa

SNP R • 3.4k views
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Maybe this link is relevant, http://membres-timc.imag.fr/Olivier.Francois/LEA/files/LEA_snmf.html

Next, we convert the FSTFST values into absolute values of zz-scores.

#convert fst values into z-scores (absolute values) 
n = dim(Q(obj.snmf, K = 2))[1]
fst.values[fst.values<0] = 0.000001
K = 2
z.scores = sqrt(fst.values*(n-K)/(1-fst.values))
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many thanks for your reply,

This is the output of the Fst stage:

enter image description here

I do not know exactly which of these columns should be z-transformed and how?

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Can someone explain why the Fst needs to be z-transformed?

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