Question: Ways to convert .impute2 to .mldose
2
gravatar for coleman_jonathan
2.8 years ago by
European Union
coleman_jonathan280 wrote:

Does anyone know of any software package that can convert .impute2 data to .mldose (i.e. imputed data from IMPUTE2 to imputed data from MACH)? I have tried impute2mach in GenABEL, but it has repeatedly failed with a known error...

Direct conversion preferred, but I'm happy with indirect as long as it works!

snp imputation • 3.8k views
ADD COMMENTlink modified 2.7 years ago • written 2.8 years ago by coleman_jonathan280

I have the same probleme, could you please tell me how to write the R script to made the dosage file ?

ADD REPLYlink written 2.7 years ago by gueliat.ines0
5
gravatar for zx8754
2.8 years ago by
zx87543.6k
London
zx87543.6k wrote:

IMPUTE output is posterior probabilities, 3 columns for 1 SNP, e.g.: 0.1 0.1 0.8 corresponding to AA AB BB. Meaning it is more likely to be BB. MACH outputs dosage, 1 column for 1 SNP, e.g.: 1.7, corresponding 0=AA, 1=AB, 2=BB, so 1.7 is more likely to be BB.

Depending on the size of the data, you can write a quick script in R that would convert posterior probabilities to dosage:

0.1*0+0.1*1+0.8*2=1.7

 

ADD COMMENTlink written 2.8 years ago by zx87543.6k
1

Thanks - that's useful, I'll give it a try!

ADD REPLYlink written 2.8 years ago by coleman_jonathan280
2
gravatar for coleman_jonathan
2.7 years ago by
European Union
coleman_jonathan280 wrote:

I have written a brief cookbook to perform this conversion in UNIX:

http://openwetware.org/wiki/User:Jonathan_R._I._Coleman/Notebook/Notes_and_Protocols/2014/06/27

ADD COMMENTlink written 2.7 years ago by coleman_jonathan280
1

The awk code for this has now been cleaned to make it more efficient (credit: Tommy Carstensen).

Alternatively, the Uni of Washington has an R package for post-Impute2 conversions: http://www.bioconductor.org/packages/release/bioc/manuals/GWASTools/man/GWASTools.pdf

ADD REPLYlink written 2.1 years ago by coleman_jonathan280
1

How does your code deal with "0 0 0", i.e.: no call? Does it convert to Ref as 0*0+0*1+0*2=0 or NA?

ADD REPLYlink written 15 months ago by zx87543.6k

My code at the time you have accessed it would convert 0 0 0 to 0 (which is wrong! I think I assumed a non-call would default to 0.33 0.33 0.33, but it doesn't). This is easily fixable (get it to set 0 0 0 to NA) - I will implement a patch. Thanks for pointing this out!

ADD REPLYlink written 14 months ago by coleman_jonathan280
2
gravatar for Joey
2.8 years ago by
Joey400
Seattle
Joey400 wrote:

You can try a program called fcgene (http://sourceforge.net/projects/fcgene/). Look into Chapter 7 of the manual which accompanies the tool.

Thanks,

-Joey

ADD COMMENTlink written 2.8 years ago by Joey400

Thanks Joey - I've already looked into this programme. Unfortunately, I think it only converts impute2 files to MACH input files (.dat and .ped), whereas I am looking for the output files.

ADD REPLYlink written 2.8 years ago by coleman_jonathan280
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