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'''minimac''' is a low memory, computationally efficient implementation of the MaCH algorithm for genotype imputation. It is designed to work on phased genotypes and can handle very large reference panels with hundreds or thousands of haplotypes. The name has two parts. The first, "mini", refers to the modest amount of computational resources it requires. The second, "mac", is short hand for [[MaCH]], our widely used algorithm for genotype imputation.
= Download =
only Linux (64 bit) version of minimac is available [http:// www.sph.umich.edu /csg/cfuchsb/minimac-beta- 2012. 8. 15.tgz from here] . The current version of minimac should be stamped 2012. 8. 15 - if your version shows a different version number or date stamp when it runs, it is not current.
If you use this beta version, please be sure to stop by the [http://www.sph.umich.edu/csg/abecasis/MaCH/download/ MaCH download page] and fill out the registration form, so that we can let you know when an official release is available and keep you updated with respect to any bug fixes.
The current version of minimac comes in two flavours, <code>minimac</code> and <code>minimac-omp</code>. The latter version uses the [[OpenMP]] protocol to support multi-threading, resulting in faster throughput.
== Change log ==
- fixed: chunk chromosome bug
=== Preparing Your Data ===
To get started, you will need to store your data in [[Merlin]] format pedigree and data files, one per chromosome. For details, of the Merlin file format, see the [http://
www.sph.umich.edu /csg/abecasis/Merlin/tour/input_files.html Merlin Tutorial].
Within each file, markers should be stored by chromosome position. Alleles should be stored in the forward strand and can be encoded as 'A', 'C', 'G' or 'T' (there is no need to use numeric identifiers for each allele).
| Data file in [http://
www.sph.umich.edu /csg/abecasis/Merlin/tour/input_files.html Merlin format]. Markers should be listed according to their order along the chromosome.
| <code>-p sample.ped</code>
| Pedigree file in [http://
www.sph.umich.edu /csg/abecasis/Merlin/tour/input_files.html Merlin format]. Alleles should be labeled on the forward strand.
| <code>--states 200</code>
A typical minimac command line might look like this:
minimac --vcfReference --refHaps ref.vcf.gz --haps target.hap.gz --snps target.snps.gz --rounds 5 --states 200 --prefix results
minimac --refHaps ref.hap.gz --refSnps ref.snps.gz --haps target.hap.gz --snps target.snps.gz --rounds 5 --states 200 --prefix results
A detailed description of all minimac options is available [[Minimac Command Reference|elsewhere]]. Here is a brief description of the above parameters:
| <code>--refHaps ref.hap.gz </code>
| Reference haplotypes (e.g. from [http://
www.sph.umich.edu /csg/abecasis/MACH/download/ MaCH download page])
| <code>--vcfReference </code>
| <code>--haps target.hap.gz </code>
| Phased haplotypes where missing genotypes will be imputed.
| <code>--rounds 5</code>
=== Reference Haplotypes ===
Reference haplotypes generated by the 1000 Genomes project and formatted so that they are ready for analysis are available from the [http://
www.sph.umich.edu /csg/abecasis/MACH/download/ MaCH download page]. As of this writing, the most recent set of haplotypes are based on genotype calls were generated in May 2011 and are an interim analysis of Project's Phase I data.
=== Imputation quality evaluation ===
=== Additional Sources of Information ===
If the combination of MaCH and Minimac still runs too slowly for you, and you have access to a multi-processor compute cluster, you can look at [[ChunkChromosome]] page to learn how to conveniently split each chromosome into multiple segments that can be analyzed in parallel.
If you are especially interested in 1000 Genomes Imputation, then you should look at the [[Minimac: 1000 Genomes Imputation Cookbook]].
= Post-imputation Association Analysis =
== Quantitative Traits ==
Please use [http://
www.sph.umich.edu /csg/yli/mach/download/mach2qtl.source.V108.tgz mach2qtl].
== Binary Traits ==
Please use [http://
www.sph.umich.edu /csg/yli/mach/download/mach2dat.source.1.0.18.tgz mach2dat]. Versions 1.0.18 and above accommodate to minimac output.
= Reference =
Howie B, Fuchsberger C, Stephens M, Marchini J, and Abecasis GR.
Fast and accurate genotype imputation in genome-wide association studies
through pre-phasing. Nature Genetics 2012 [http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.2354.html]
= Related Pages =