GSP
Quick Navigator

Search Site

Unix VPS
A - Starter
B - Basic
C - Preferred
D - Commercial
MPS - Dedicated
Previous VPSs
* Sign Up! *

Support
Contact Us
Online Help
Handbooks
Domain Status
Man Pages

FAQ
Virtual Servers
Pricing
Billing
Technical

Network
Facilities
Connectivity
Topology Map

Miscellaneous
Server Agreement
Year 2038
Credits
 

USA Flag

 

 

Man Pages
IHS(1) iHS (VCF statistics) IHS(1)

iHS

iHS –target 0,1,2,3,4,5,6,7 –file my.phased.vcf  –region chr1:1-1000 > STDOUT 2> STDERR

iHS calculates the integrated haplotype score which measures the relative decay of extended haplotype homozygosity (EHH) for the reference and alternative alleles at a site (see: voight et al. 2006, Spiech & Hernandez 2014).


Our code is highly concordant with both implementations mentioned. However, we do not set an upper limit to the allele frequency.  **iHS** can be run without a genetic map, in which case the change in EHH is integrated over a constant.  Human genetic maps for GRCh36 and GRCh37 (hg18 & hg19) can be found at: http://bochet.gcc.biostat.washington.edu/beagle/genetic_maps/ . **iHS** by default interpolates SNV positions to genetic position (you don't need a genetic position for every VCF entry in the map file).
**iHS** analyses requires normalization by allele frequency.  It is important that **iHS** is calculated over large regions so that the normalization does not down weight real signals.  For genome-wide runs it is recommended to run slightly overlapping windows and throwing out values that fail integration (columns 7 & 8 in the output) and then removing duplicates by using the 'sort' and 'uniq' linux commands.  Normalization of the output is as simple as running 'normalize-**iHS**'.
     **iHS** calculates the integrated ratio of haplotype decay between the reference and non-reference allele.
Output : 4 columns :
     1. seqid
     2. position
     3. target allele frequency
     4. integrated EHH (alternative)
     5. integrated EHH (reference)
     6. **iHS** ln(iEHHalt/iEHHref)
     7. != 0 integration failure
     8. != 0 integration failure
Params:
       required: t,target  <STRING>  A zero base comma separated list of target
                                     individuals corresponding to VCF columns
       required: r,region  <STRING>  A tabix compliant genomic range
                                     format: "seqid:start-end" or "seqid"
       required: f,file    <STRING>  Proper formatted and phased VCF.
       required: y,type    <STRING>  Genotype likelihood format: GT,PL,GL,GP
       optional: a,af      <DOUBLE>  Alternative alleles with frquences less
                                     than [0.05] are skipped.
       optional: x,threads <INT>     Number of CPUS [1].
       recommended: g,gen <STRING>   A PLINK formatted map file.
Type: statistics

    

0
Success
not 0
Failure

vcflib(1)

Copyright 2011-2022 (C) Erik Garrison and vcflib contributors. MIT licensed.

Erik Garrison and vcflib contributors.
iHS (vcflib)

Search for    or go to Top of page |  Section 1 |  Main Index

Powered by GSP Visit the GSP FreeBSD Man Page Interface.
Output converted with ManDoc.