gtx (version 0.0.8)

Genetics ToolboX

Description

Assorted tools for genetic association analyses. The current focus is on implementing (either exactly or approximately) regression analyses using summary statistics instead of using subject-specific data. So far, functions exist to support multi-SNP risk score analyses, multi-SNP conditional regression analyses, and multi-phenotype analyses, using summary statistics. There are helper functions for reading and manipulating subject-specific genotype data, which provide a platform for calculating the summary statistics, or for using R to conduct other analyses not supported by specific GWAS analysis tools.

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Version

Install

install.packages('gtx')

Monthly Downloads

32

Version

0.0.8

License

GPL (>= 2)

Maintainer

Last Published

January 11th, 2013

Functions in gtx (0.0.8)

gls.approx.logistic

Calculate weights and transformed phenotype so that one iteration of generalised least squares approximates a logistic regression.
grs.filter.Qrs

Filter SNPs for inclusion in genetic risk score using heterogeneity test.
cad.scores

Genetic risk scores for coronary artery disease risk
abf.Wakefield

Calculate approximate Bayes factor (ABF) using method of Wakefield (2009).
coeff.extract

Coefficient extractor for fitted models.
fitmix

Fit finite mixture of univariate Gaussian densities to data.
hapmap.snpdata

Extract individual level snp/haplotype data from HapMap
agtstats

Hypertension association statistics for SNPs near the AGT gene.
grs.summary

Genetic risk score calculation from summary statistics.
abf.normal

Calculate approximate Bayes factor (ABF) for normal prior.
grs.plot

Diagnostic plot for genetic risk score calculation from summary statistics.
align.snpdata.coding

Update genotype coding when there are coded allele designation flips.
gtx-package

Genetics ToolboX
combine.moments2

Builds a matrix of second moments for a set of individuals, from the matrices of second moments for all constituent subsets of individuals.
liver.scores

Genetic risk scores for liver enzyme traits.
chi2ncp

Compute non-centrality parameter of chi squared distribution.
t2dex

Simulated example genotype and longitudinal phenotype data.
lipid.scores

Genetic risk scores for serum lipid levels
hapmap.read.haplotypes

Read hapmap haplotypes.
abf.t

Calculate approximate Bayes factor (ABF) for t distribution prior.
fitmix.simulate

Simulate from finite mixture of univariate Gaussian densities.
mthfrex

Simulated example finemapping genotype and phenotype data.
snpdata

Class for SNP genotype and phenotype data.
snphwe

Exact test of Hardy--Weinberg.
multimatch

Match with multiple matching possible.
snphweCounts

Exact test of Hardy--Weinberg.
stepup.moments2

Stepwise upward model selection using summary statistic matrix.
mincover

Compute minimum size of cover of overlapping intervals.
multipheno.T2

Multi-phenotype test for association
t2d.scores

Genetic risk scores for type 2 diabetes risk.
test.subsample

Test approximation used in genetic risk score analyses.
gtx.params

Parameter format for multi-SNP analyses
stepdown.moments2

Stepwise downward model selection using summary statistic matrix.
snps.BRCA1

Genotyping array annotation for SNPs near the BRCA1 gene.
magic.scores

Genetic risk scores for glucose/insulin traits.
read.snpdata.minimac

Read genotype dosages in the format output by minimac
read.snpdata.impute

Read genotype dosages in the format output by IMPUTE.
lm.moments2

Fit normal linear model using pre-built matrix of second moments.
read.snpdata.mach

Read genotype dosages in the format output by MACH
moments2

Class for summary statistic matrix of second moments.
grs.make.scores

Make genetic risk scores from individual-level data.
read.snpdata.plink

Read genotype dosages in the format output by PLINK.
allelesAB

Paste together (vectors of) A and B alleles after sorting alphabetically.
contrasting.rainbow

Rainbow of colours permuted to maximise contrast.
est.moments2

Estimate regression coefficients using quadratic approximation to likelihood function.
lipid.cad.scores

Genetic risk scores for serum lipid levels and coronary artery disease outcome
bp.scores

Genetic risk scores for blood pressure.
sanitise.whitespace

Remove leading and trailing spaces; convert double spaces to single spaces.
height.scores

Genetic risk score for height.
fitmix.r2

For finite mixture of univariate Gaussian densities, computes proportion of variance explained by the mixture labels.
parse.snps

Parse text representation of a SNP embedded in flanking sequences.
fitmix.plot

Plot empirical density and components and total density for finite mixture of univariate Gaussian densities.
grs.onesnp.apply

Convenience tool to fit a series of single-SNP models.
remap.q2t

Remap coordinates from BLAT query sequence to BLAT target sequence.
make.moments2

Build matrix of second moments from subject-specific data.