, Dolors Pelegri [aut,
cre] | Title: | SNPs-Based Whole Genome Association Studies |
|---|---|
| Description: | Functions to perform most of the common analysis in genome association studies are implemented. These analyses include descriptive statistics and exploratory analysis of missing values, calculation of Hardy-Weinberg equilibrium, analysis of association based on generalized linear models (either for quantitative or binary traits), and analysis of multiple SNPs (haplotype and epistasis analysis). Permutation test and related tests (sum statistic and truncated product) are also implemented. Max-statistic and genetic risk-allele score exact distributions are also possible to be estimated. The methods are described in Gonzalez JR et al., 2007 <doi: 10.1093/bioinformatics/btm025>. |
| Authors: | Victor Moreno [aut], Juan R Gonzalez [aut]
, Dolors Pelegri [aut,
cre] |
| Maintainer: | Dolors Pelegri <[email protected]> |
| License: | GPL (>= 2) |
| Version: | 2.1-2 |
| Built: | 2024-10-29 06:54:03 UTC |
| Source: | CRAN |
This function carries out an association analysis between a single SNP and a dependent variable (phenotype) under five different genetic models (inheritance patterns): codominant, dominant, recessive, overdominant and log-additive. The phenotype may be quantitative or categorical. In the second case (e.g. case-control studies) this variable must be of class 'factor' with two levels.
association(formula, data, model=c("all"), model.interaction= c("codominant"), subset, name.snp = NULL, quantitative = is.quantitative(formula,data), genotypingRate= 0, level = 0.95, ...)association(formula, data, model=c("all"), model.interaction= c("codominant"), subset, name.snp = NULL, quantitative = is.quantitative(formula,data), genotypingRate= 0, level = 0.95, ...)
formula |
a symbolic description of the model to be fited (a formula object).
It might have either a continuous variable (quantitative traits) or a
factor variable (case-control studies) as the response on the left of the |
data |
a required dataframe of class 'setupSNP' containing the variables in the model. |
model |
a character string specifying the type of genetic model (mode of inheritance) for the SNP. This indicates how the genotypes should be collapsed. Possible values are "codominant", "dominant", "recessive", "overdominant", "additive" or "all". The default is "all" that fits the 5 possible genetic models. Only the first words are required, e.g "co", "do", etc. |
model.interaction |
a character string specifying the type of genetic model (mode of inheritance) assumed for the SNP when it is included in a interaction term. Possible values are "codominant", "dominant", "recessive", "overdominant". The default is "codominant". |
subset |
an optional vector specifying a subset of observations to be used in the fitting process |
name.snp |
optional label of the SNP variable to be printed. |
quantitative |
logical value indicating whether the phenotype (that which is in the left of the operator ~ in 'formula' argument) is quantitative. The function 'is.quantitative' returns FALSE when the phenotype is a variable with two categories (i.e. indicating case-control status). Thus, it is not a required argument but it may be modified by the user. |
genotypingRate |
minimum percentage of genotype rate for the SNP to be analyzed. Default is 0% (e.g. all SNPs are analyzed). This parameter should not be changed. It is used in the function 'WGassociation'. |
level |
signification level for confidence intervals. |
... |
Other arguments to be passed through glm function |
This function should be called by the user when we are interested in analyzing an unique SNP.
It is recommended to use WGassociation function when more than one SNP is studied.
For each genetic model (codominant, dominant, recessive, overdominant, and log-additive) the function gives a matrix with sample size and percentages for each genotype, the Odds Ratio and its 95% confidence interval (taking the most frequent homozygous genotype as the reference), the p-value corresponding to the likelihood ratio test obtained from a comparison with the null model, and the Akaike Information Criterion (AIC) of each genetic model. In the case of analyzing a quantitative trait, the function returns a matrix with sample size, mean and standard errors for each genotype, mean difference and its 95% confidence interval with respect to the most frequent homozygous genotype, the p-value obtained from an overall gene effect and the Akaike Information Criterion (AIC) of each genetic model.
When an interaction term (a categorical covariate with an SNP) is included in the model, three different tables are given. The first one correponds to the full interaction matrix where the ORs (or mean differences if a quantitative trait is analyzed) are expressed with respect to the non variant genotype and the first category of the covariate. The other two tables show the ORs and their 95% confidence intervals for both marginal models. P values for interaction and trend are also showed in the output.
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
Iniesta R, Guino E, Moreno V. Statistical analysis of genetic polymorphisms in epidemiological studies. Gac Sanit. 2005;19(4):333-41.
Elston RC. Introduction and overview. Statistical methods in genetic epidemiology. Stat Methods Med Res. 2000;9:527-41.
data(SNPs) # first, we create an object of class 'setupSNP' datSNP<-setupSNP(SNPs,6:40,sep="") # case-control study, crude analysis association(casco~snp10001, data=datSNP) # case-control study, adjusted by sex and arterial blood pressure association(casco~sex+snp10001+blood.pre, data=datSNP) # quantitative trait, crude analysis association(log(protein)~snp10001,data=datSNP) # quantitative trait, adjusted by sex association(log(protein)~snp10001+sex,data=datSNP) # # Interaction analysis # # Interaction SNP and factor association(log(protein)~snp10001*sex+blood.pre, data=datSNP, model="codominant") # Interaction SNP and SNP (codominant and codominant) association(log(protein)~snp10001*factor(snp10002)+blood.pre, data=datSNP, model="codominant") # Interaction SNP and SNP (dominant and recessive) association(log(protein)~snp10001*factor(recessive(snp100019))+blood.pre, data=datSNP, model="dominant")data(SNPs) # first, we create an object of class 'setupSNP' datSNP<-setupSNP(SNPs,6:40,sep="") # case-control study, crude analysis association(casco~snp10001, data=datSNP) # case-control study, adjusted by sex and arterial blood pressure association(casco~sex+snp10001+blood.pre, data=datSNP) # quantitative trait, crude analysis association(log(protein)~snp10001,data=datSNP) # quantitative trait, adjusted by sex association(log(protein)~snp10001+sex,data=datSNP) # # Interaction analysis # # Interaction SNP and factor association(log(protein)~snp10001*sex+blood.pre, data=datSNP, model="codominant") # Interaction SNP and SNP (codominant and codominant) association(log(protein)~snp10001*factor(snp10002)+blood.pre, data=datSNP, model="codominant") # Interaction SNP and SNP (dominant and recessive) association(log(protein)~snp10001*factor(recessive(snp100019))+blood.pre, data=datSNP, model="dominant")
data.frame with 51 SNPs and 6 epidemiological variables: country, gender, age, bmi, smoke ans case/control status.
data("asthma")data("asthma")
The asthma data frame has 1578 rows (individuals) and 57 columns (variables) of data from a genetic study on asthma.
An data.frame object.
data(asthma) dim(asthma) str(asthma)data(asthma) dim(asthma) str(asthma)
This function shows the SNPs that are statistically significant after correcting for the number of tests performed (Bonferroni correction) for an object of class "WGassociation"
Bonferroni.sig(x, model = "codominant", alpha = 0.05, include.all.SNPs=FALSE)Bonferroni.sig(x, model = "codominant", alpha = 0.05, include.all.SNPs=FALSE)
x |
an object of class 'WGassociation'. |
model |
a character string specifying the type of genetic model (mode of inheritance). This indicantes how the genotypes should be collapsed when 'plot.summary' is TRUE. Possible values are "codominant", "dominant", "recessive", "overdominant", or "log-additive". The default is "codominant". Only the first words are required, e.g "co", "do", ... . |
alpha |
nominal level of significance. Default is 0.05 |
include.all.SNPs |
logical value indicating whether all SNPs are considered in the Bonferroni
correction. That is, the number of performed tests is equal to the number of SNPs or equal to the
number of SNPs where a p value may be computed. The default value is FALSE indicating that the
number of tests is equal to the number of SNPs that are non Monomorphic and the rate of genotyping
is greater than the percentage indicated in the |
After deciding the genetic model, the function shows the SNPs that are statistically significant at
alpha level corrected by the number of performed tests.
A data frame with the SNPs and the p values for those SNPs that are statistically significant after Bonferroni correction
data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ans<-WGassociation(protein~1,data=datSNP,model="all") Bonferroni.sig(ans, model="codominant", alpha=0.05, include.all.SNPs=FALSE)data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ans<-WGassociation(protein~1,data=datSNP,model="all") Bonferroni.sig(ans, model="codominant", alpha=0.05, include.all.SNPs=FALSE)
This function estimates an inflation (or deflation) factor, lambda, as indicated in the paper by Devlin et al. (2001) and corrects the p-values using this factor.
GenomicControl(x, snp.sel)GenomicControl(x, snp.sel)
x |
an object of class 'WGassociation'. |
snp.sel |
SNPs used to compute lambda. Not required. |
This method is only valid for 2x2 tables. This means that the object of class 'WGassociation' might not have fitted the codominant model.
See reference for further details.
The same object of class 'WGassociation' where the p-values have been corrected for genomic control.
B Devlin, K Roeder, and S.A. Bacanu. Unbiased Methods for Population Based Association Studies. Genetic Epidemiology (2001) 21:273-84
data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") res<-WGassociation(casco,datSNP,model=c("do","re","log-add")) # Genomic Control resCorrected<-GenomicControl(res)data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") res<-WGassociation(casco,datSNP,model=c("do","re","log-add")) # Genomic Control resCorrected<-GenomicControl(res)
Get gene symbol from a list of SNPs
getGeneSymbol( x, snpCol = 1, chrCol = 2, posCol = 3, db = TxDb.Hsapiens.UCSC.hg19.knownGene )getGeneSymbol( x, snpCol = 1, chrCol = 2, posCol = 3, db = TxDb.Hsapiens.UCSC.hg19.knownGene )
x |
data.frame containing: SNP name, chromosome and genomic position. |
snpCol |
column of x having the SNP name. Default is 1. |
chrCol |
column of x having the SNP chromosome. Default is 2. |
posCol |
column of x having the SNP position. Default is 3. |
db |
reference genome. Default is 'TxDb.Hsapiens.UCSC.hg19.knownGene' |
a data.frame having initial information and gene symbol
snps = c('rs58108140','rs189107123','rs180734498','rs144762171') chr = c('chr1','chr1','chr1','chr1') pos = c(10583, 10611, 13302, 13327) x <- data.frame(snps, chr, pos ) getGeneSymbol(x)snps = c('rs58108140','rs189107123','rs180734498','rs144762171') chr = c('chr1','chr1','chr1','chr1') pos = c(10583, 10611, 13302, 13327) x <- data.frame(snps, chr, pos ) getGeneSymbol(x)
Create Latex output from association analyses
getNiceTable( x )getNiceTable( x )
x |
WGassociation object. |
The R output of specific association analyses exported into LaTeX
Extract significant SNPs from an object of class 'WGassociation' when genomic information is available
getSignificantSNPs(x, chromosome, model, sig = 1e-15)getSignificantSNPs(x, chromosome, model, sig = 1e-15)
x |
an object of class 'WGassociation' |
chromosome |
chromosome from which SNPs are extracted |
model |
genetic model from which SNPs are extracted |
sig |
statistical significance level. The default is 1e-15 |
A list with the following components:
names |
the name of SNPs |
column |
the columns corresponding to the SNPs in the original data frame |
...
data(resHapMap) # resHapMap contains the results for a log-additive genetic model # to get the significant SNPs for chromosome 12 getSignificantSNPs(resHapMap,chromosome=12) # to get the significant SNPs for chromosome 5 getSignificantSNPs(resHapMap,5) # to get the significant SNPs for chromosome X at level 1e-8 getSignificantSNPs(resHapMap,5,sig=1e-8)data(resHapMap) # resHapMap contains the results for a log-additive genetic model # to get the significant SNPs for chromosome 12 getSignificantSNPs(resHapMap,chromosome=12) # to get the significant SNPs for chromosome 5 getSignificantSNPs(resHapMap,5) # to get the significant SNPs for chromosome X at level 1e-8 getSignificantSNPs(resHapMap,5,sig=1e-8)
This function computes the ORs (or mean differences if a quantitative trait is analyzed) and their 95% confidence intervals corresponding to an interaction between the haplotypes and a categorical covariate
haplo.interaction(formula, data, SNPs.sel, quantitative = is.quantitative(formula, data), haplo.freq.min = 0.05, ...)haplo.interaction(formula, data, SNPs.sel, quantitative = is.quantitative(formula, data), haplo.freq.min = 0.05, ...)
formula |
a symbolic description of the model to be fitted (a formula object).
It might have either a continuous variable (quantitative traits) or a
factor variable (case-control studies) as the response on the left of the |
data |
an object of class 'setupSNP' containing the variables in the model and the SNPs that will be used to estimate the haplotypes. |
SNPs.sel |
a vector indicating the names of SNPs that are used to estimate the haplotypes |
quantitative |
logical value indicating whether the phenotype (which is on the
left of the operator |
haplo.freq.min |
control parameter for haplo.glm included in 'haplo.glm.control'. This parameter corresponds to the minimum haplotype frequency for a haplotype to be included in the regression model as its own effect. The haplotype frequency is based on the EM algorithm that estimates haplotype frequencies independently of any trait. |
... |
additional parameters for 'haplo.glm.control'. |
The function estimates the haplotypes for the SNPs indicated in the 'SNPs.sel' argument. Then, usign 'haplo.glm' function (from 'haplo.stats' library) estimates the interaction between these haplotypes and the covariate indicated in the formula by means of 'interaction' function.
Three different tables are given. The first one corresponds to the full interaction matrix where the ORs (or mean differences if a quantitative trait is analyzed) are expressed with respect to the most frequent haplotype and the first category of the covariate. The other two tables show the ORs (or mean differences if a quantitative trait is analyzed) and their 95% confidence intervals for both marginal models. P values for interaction are also showed in the output.
# not Run library(SNPassoc) library(haplo.stats) data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") res <- haplo.interaction(log(protein)~int(sex), data=datSNP, SNPs.sel=c("snp100019","snp10001","snp100029")) res# not Run library(SNPassoc) library(haplo.stats) data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") res <- haplo.interaction(log(protein)~int(sex), data=datSNP, SNPs.sel=c("snp100019","snp10001","snp100029")) res
Information about 9307 SNPs from the HapMap project belonging to 22 chromosomes. Information about two different population is available: European population (CEU) and Yoruba (YRI). The genomic information (names of SNPs, chromosomes and genetic position) is also available in a data frame called 'HapMap.SNPs.pos'.
data(HapMap)data(HapMap)
A data frame with 120 observations on the 9808 variables (SNPs) and one variable called 'group' indicating the population.
HapMap project (http://www.hapmap.org)
data(HapMap)data(HapMap)
Information about 9307 SNPs from the HapMap project belonging to 22 chromosomes. Information about two different population is available: European population (CEU) and Yoruba (YRI). The genomic information (names of SNPs, chromosomes and genetic position) is also available in a data frame called 'HapMap.SNPs.pos'.
data(HapMap.SNPs.pos)data(HapMap.SNPs.pos)
A data frame with 120 observations on the 9808 variables (SNPs) and one variable called 'group' indicating the population.
HapMap project (http://www.hapmap.org)
data(HapMap.SNPs.pos)data(HapMap.SNPs.pos)
codominant function recodifies a variable having genotypes depending on the allelic frequency
in descending order.
dominant, recessive, and overdominant functions collapse the three categories of a given SNP
into two categories as follows: Let 'AA', 'Aa', and 'aa' be the three genotypes. After determining
the most frequent allele (let's suppose that 'A' is the major allele) the functions return a vector
with to categories as follows. dominant: 'AA' and 'Aa-aa'; recessive: 'AA-Aa' and 'aa';
overdominant: 'AA-aa' vs 'Aa'.
additive function creates a numerical variable, 1, 2, 3 corresponding to the three genotypes sorted out by descending allelic frequency (this model is referred as log-additive).
codominant(o) dominant(o) recessive(o) overdominant(o) additive(o)codominant(o) dominant(o) recessive(o) overdominant(o) additive(o)
o |
categorical covariate having genotypes |
A snp object collapsing genotypes into different categories depending on a given genetic mode of inheritance
data(SNPs) dominant(snp(SNPs$snp10001,sep="")) overdominant(snp(SNPs$snp10001,sep=""))data(SNPs) dominant(snp(SNPs$snp10001,sep="")) overdominant(snp(SNPs$snp10001,sep=""))
This is a special function used for 'haplo.interaction' function. It
identifies the variable that will interact with the haplotype estimates.
Using int() in a formula implies that
the interaction term between this variable and haplotypes is included in 'haplo.glm' function.
int(x)int(x)
x |
A factor variable. |
x
library(SNPassoc) library(haplo.stats) data(SNPs) datSNP<-setupSNP(SNPs, 6:40, sep = "") mod <- haplo.interaction(casco~int(sex)+blood.pre, data = datSNP, SNPs.sel = c("snp10001","snp10004","snp10005"))library(SNPassoc) library(haplo.stats) data(SNPs) datSNP<-setupSNP(SNPs, 6:40, sep = "") mod <- haplo.interaction(casco~int(sex)+blood.pre, data = datSNP, SNPs.sel = c("snp10001","snp10004","snp10005"))
Perform a two-dimensional SNP analysis (interaction) for association studies with possible allowance for covariate
interactionPval(formula, data, quantitative = is.quantitative(formula, data), model = "codominant")interactionPval(formula, data, quantitative = is.quantitative(formula, data), model = "codominant")
formula |
a formula object. It might have either a continuous variable (quantitative traits) or a
factor variable (case-control study) as the response on the left of the |
data |
a required object of class 'setupSNP'. |
quantitative |
logical value indicating whether the phenotype (those which is in the left of the operator ~ in 'formula' argument) is quantitative. The function 'is.quantitative' returns FALSE when the phenotype is a variable with two categories (i.e. indicating case-control status). Thus, it is not a required argument but it may be modified by the user. |
model |
a character string specifying the type of genetic model (mode of inheritance). This indicates how the genotypes should be collapsed. Possible value are "codominant", "dominant", "recessive", "overdominant" or "log-additive". The default is "codominant". Only the first words are required, e.g "co", "do", "re", "ov", "log" |
The 'interactionPval' function calculates, for each pair of SNPs (i,j), the likelihood underling the null model L0, the likelihood under each of the single-SNP, L(i) and L(j), the likelihood under an additive SNP model La(i,j), and the likelihood under a full SNP model (including SNP-SNP interaction), Lf(i,j).
The upper triangle in matrix from this function contains the p values for the interaction (epistasis) log-likelihood ratio test, LRT, LRTij = -2 (log Lf(i,j) - log La(i,j))
The diagonal contains the p values from LRT for the crude effect of each SNP, LRTii = -2 (log L(i) - log L0)
The lower triangle contains the p values from LRT comparing the two-SNP additive likelihood to the best of the single-SNP models, LRTji = -2 (log La(i,j) - log max(L(i),L(j)))
In all cases the models including the SNPs are adjusted by the covariates indicated in the 'formula' argument. This method is used either for quantitative traits and dicotomous variables (case-control studies).
The 'interactionPval' function returns a matrix of class 'SNPinteraction' containing the p values corresponding to the different likelihood ratio tests above describe.
Methods defined for 'SNPinteraction' objects are provided for print and plot. The plot method uses 'image' to plot a grid of p values. The upper triangle contains the interaction (epistasis) p values from LRT. The content in the lower triangle is the p values from the LRT comparing the additive model with the best single model. The diagonal contains the main effects pvalues from LRT. The 'plot.SNPinteraction' function also allows the user to plot the SNPs sorted by genomic position and with the information about chromosomes as in the 'plotMissing' function.
two-dimensional SNP analysis on a dense grid can take a great deal of computer time and memory.
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ansCod<-interactionPval(log(protein)~sex,datSNP) print(ansCod) plot(ansCod)data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ansCod<-interactionPval(log(protein)~sex,datSNP) print(ansCod) plot(ansCod)
Print ORs and confidence intervals for an object of class 'haplo.glm'
intervals(o, level=.95, ...)intervals(o, level=.95, ...)
o |
object of class 'haplo.glm' |
level |
significance level. Default is 95 percent |
... |
other arguments |
intervals object with ORs and 95% confidence intervals for an object of class 'haplo.glm'
# Not Run library(SNPassoc) library(haplo.stats) data(asthma, package = "SNPassoc") asthma.s <- setupSNP(data=asthma, colSNPs=7:ncol(asthma), sep="") trait <- asthma.s$casecontrol snpsH <- c("rs714588", "rs1023555", "rs898070") genoH <- make.geno(asthma.s, snpsH) mod <- haplo.stats:: haplo.glm( trait ~ genoH, family="binomial", locus.label=snpsH, allele.lev=attributes(genoH)$unique.alleles, control = haplo.glm.control(haplo.freq.min=0.05)) intervals(mod) summary(mod)# Not Run library(SNPassoc) library(haplo.stats) data(asthma, package = "SNPassoc") asthma.s <- setupSNP(data=asthma, colSNPs=7:ncol(asthma), sep="") trait <- asthma.s$casecontrol snpsH <- c("rs714588", "rs1023555", "rs898070") genoH <- make.geno(asthma.s, snpsH) mod <- haplo.stats:: haplo.glm( trait ~ genoH, family="binomial", locus.label=snpsH, allele.lev=attributes(genoH)$unique.alleles, control = haplo.glm.control(haplo.freq.min=0.05)) intervals(mod) summary(mod)
Compute pairwise linkage disequilibrium between genetic markers
LD(g1, ...) ## S3 method for class 'snp' LD(g1, g2, ...) ## S3 method for class 'setupSNP' LD(g1, SNPs, ...) LDplot(x, digits = 3, marker, distance, which = c("D", "D'", "r", "X^2", "P-value", "n", " "), ...) LDtable(x, colorcut = c(0, 0.01, 0.025, 0.05, 0.1, 1), colors = heat.colors(length(colorcut)), textcol = "black", digits = 3, show.all = FALSE, which = c("D", "D'", "r", "X^2", "P-value", "n"), colorize = "P-value", cex, ...)LD(g1, ...) ## S3 method for class 'snp' LD(g1, g2, ...) ## S3 method for class 'setupSNP' LD(g1, SNPs, ...) LDplot(x, digits = 3, marker, distance, which = c("D", "D'", "r", "X^2", "P-value", "n", " "), ...) LDtable(x, colorcut = c(0, 0.01, 0.025, 0.05, 0.1, 1), colors = heat.colors(length(colorcut)), textcol = "black", digits = 3, show.all = FALSE, which = c("D", "D'", "r", "X^2", "P-value", "n"), colorize = "P-value", cex, ...)
g1 |
genotype object or dataframe containing genotype objects |
g2 |
genotype object (ignored if g1 is a dataframe) |
SNPs |
columns containing SNPs |
x |
LD or LD.data.frame object |
digits |
Number of significant digits to display |
which |
Name(s) of LD information items to be displayed |
colorcut |
P-value cutoffs points for colorizing LDtable |
colors |
Colors for each P-value cutoff given in 'colorcut' for LDtable |
textcol |
Color for text labels for LDtable |
marker |
Marker used as 'comparator' on LDplot. If omitted separate lines for each marker will be displayed |
distance |
Marker location, used for locating of markers on LDplot. |
show.all |
If TRUE, show all rows/columns of matrix. Otherwise omit completely blank rows/columns. |
colorize |
LD parameter used for determining table cell colors |
cex |
Scaling factor for table text. If absent, text will be scaled to fit within the table cells. |
... |
Optional arguments ('plot.LD.data.frame' passes these to 'LDtable' and 'LDplot'). |
None
functions adapted from LD, LDtable and LDplot in package genetics by Gregory Warnes et al. ([email protected])
genetics R package by Gregory Warnes et al. ([email protected])
This function prepares the CRITICAL element corresponding to matrix of genotypes necessary to be included in 'haplo.glm' function.
make.geno(data, SNPs.sel)make.geno(data, SNPs.sel)
data |
an object of class 'setupSNP' containing the the SNPs that will be used to estimate the haplotypes. |
SNPs.sel |
a vector indicating the names of SNPs that are used to estimate the haplotypes |
the same as 'setupGeno' function, from 'haplo.stats' library, returns
## Not run: data(SNPs) # first, we create an object of class 'setupSNP' datSNP<-setupSNP(SNPs,6:40,sep="") geno<-make.geno(datSNP,c("snp10001","snp10002","snp10003")) ## End(Not run)## Not run: data(SNPs) # first, we create an object of class 'setupSNP' datSNP<-setupSNP(SNPs,6:40,sep="") geno<-make.geno(datSNP,c("snp10001","snp10002","snp10003")) ## End(Not run)
Computes the asymptotic p-value for max-statistic for a 2x3 table
maxstat(x, ...) ## Default S3 method: maxstat(x, y, ...) ## S3 method for class 'table' maxstat(x, ...) ## S3 method for class 'setupSNP' maxstat(x, y, colSNPs=attr(x,"colSNPs"), ...) ## S3 method for class 'matrix' maxstat(x, ...)maxstat(x, ...) ## Default S3 method: maxstat(x, y, ...) ## S3 method for class 'table' maxstat(x, ...) ## S3 method for class 'setupSNP' maxstat(x, y, colSNPs=attr(x,"colSNPs"), ...) ## S3 method for class 'matrix' maxstat(x, ...)
x |
a numeric matrix with 2 rows (cases/controls) and 3 colums (genotypes) or a vector with case/control status or an object of class 'setupSNP'. |
y |
an optional numeric vector containing the information for a given SNP. In this case 'x' argument must contain a vector indicarting case/control status. If 'x' argument is an object of class 'setupSNP' this argument migth be the name of the variable containing case/control information. |
colSNPs |
a vector indicating which columns contain those SNPs to compute max-statistic. By default max-statistic is computed for those SNPs specified when the object of class 'setupSNP' was created. |
... |
further arguments to be passed to or from methods. |
A matrix with the chi-square statistic for dominant, recessive, log-additive and max-statistic and its asymptotic p-value.
Gonzalez JR, Carrasco JL, Dudbridge F, Armengol L, Estivill X, Moreno V. Maximizing association statistics over genetic models (2007). Submitted
Sladek R, Rocheleau G, Rung J et al. A genome-wide association study identifies novel risk loci for type 2 diabetes (2007). Nature 445, 881-885
# example from Sladek et al. (2007) for the SNP rs1111875 tt<-matrix(c(77,298,310,122,316,231),nrow=2,ncol=3,byrow=TRUE) maxstat(tt) data(SNPs) maxstat(SNPs$casco,SNPs$snp10001) myDat<-setupSNP(SNPs,6:40,sep="") maxstat(myDat,casco)# example from Sladek et al. (2007) for the SNP rs1111875 tt<-matrix(c(77,298,310,122,316,231),nrow=2,ncol=3,byrow=TRUE) maxstat(tt) data(SNPs) maxstat(SNPs$casco,SNPs$snp10001) myDat<-setupSNP(SNPs,6:40,sep="") maxstat(myDat,casco)
Extract odds ratios, 95
odds(x, model=c("log-additive", "dominant", "recessive", "overdominant", "codominant"), sorted=c("no","p-value","or"))odds(x, model=c("log-additive", "dominant", "recessive", "overdominant", "codominant"), sorted=c("no","p-value","or"))
x |
an object of class 'WGassociation' output of WGassociation |
model |
model to be extracted. Only first one is used. The first letter is enough, low or upper case. |
sorted |
Sort the output by P value or OR. |
A matrix with OR 95% CI (lower, upper) and P value for the selected model. For codominant model, the OR and 95%CI are given for heterozygous and homozigous.
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ans<-WGassociation(casco~1,data=datSNP,model="all") odds(ans)data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ans<-WGassociation(casco~1,data=datSNP,model="all") odds(ans)
This function extract the p values for permutation approach performed using scanWGassociation function
permTest(x, method="minimum", K)permTest(x, method="minimum", K)
x |
a required object of class 'WGassociation' with the attribute 'permTest'. See details |
method |
statistic used in the permutation test. The default is 'minimum' but 'rtp' (rank truncated product) is also available. |
K |
number of the K most significant p values from the total number of test performed (e.g number of SNPs) used to compute the rank truncated product. This argument is only required when method='rtp'. See references |
This function extract the p values from an object of class 'WGassociation'. This object migth be obtained using the funcion called 'scanWGassociation' indicating the number of permutations in the argument 'nperm'.
An object of class 'permTest'.
'print' returns a summary indicating the number of SNPs analyzed, the number of valid SNPs (those non-Monomorphic and that pass the calling rate), the p value after Bonferroni correction, and the p values based on permutation approach. One of them is based on considering the empirical percentil for the minimum p values, and the another one on assuming that the minimum p values follow a beta distribution.
'plot' produces a plot of the empirical distribution for the minimum p values (histogram) and the expected distribution assuming a beta distribution. The corrected p value is also showed in the plot.
See examples for further illustration about all previous issues.
Dudbridge F, Gusnanto A and Koeleman BPC. Detecting multiple associations in genome-wide studies. Human Genomics, 2006;2:310-317.
Dudbridge F and Koeleman BPC. Efficient computation of significance levels for multiple associations in large studies of correlated data, including genomewide association studies. Am J Hum Genet, 2004;75:424-435.
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
library(SNPassoc) data(asthma, package = "SNPassoc") asthma.s <- setupSNP(data=asthma, colSNPs=7:ncol(asthma), sep="") ans <- WGassociation(casecontrol, data=asthma.s)library(SNPassoc) data(asthma, package = "SNPassoc") asthma.s <- setupSNP(data=asthma, colSNPs=7:ncol(asthma), sep="") ans <- WGassociation(casecontrol, data=asthma.s)
Function to plot -log p values from an object of class 'WGassociation'
## S3 method for class 'WGassociation' plot(x, ...)## S3 method for class 'WGassociation' plot(x, ...)
x |
an object of class 'WGassociation' |
... |
other graphical parameters |
A panel with different plots (one for each mode of inheritance) are plotted. Each of them represents the -log(p value) for each SNP. Two horizontal lines are also plotted. One one them indicates the nominal statistical significance level whereas the other one indicates the statistical significance level after Bonferroni correction.
No return value, just the plot
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
association setupSNP WGassociation
library(SNPassoc) data(asthma, package = "SNPassoc") asthma.s <- setupSNP(data=asthma, colSNPs=7:ncol(asthma), sep="") ans <- WGassociation(casecontrol, data=asthma.s) plot(ans)library(SNPassoc) data(asthma, package = "SNPassoc") asthma.s <- setupSNP(data=asthma, colSNPs=7:ncol(asthma), sep="") ans <- WGassociation(casecontrol, data=asthma.s) plot(ans)
Plot a grid showing which genotypes are missing
plotMissing(x, print.labels.SNPs = TRUE, main = "Genotype missing data", ...)plotMissing(x, print.labels.SNPs = TRUE, main = "Genotype missing data", ...)
x |
an object of class 'setupSNP' |
print.labels.SNPs |
should labels of SNPs be printed? |
main |
title to place on plot |
... |
extra arguments of 'image' function |
This function uses 'image' function to plot a grid with black pixels where the genotypes are missing.
No return value, just the plot
data(SNPs) data(SNPs.info.pos) ans<-setupSNP(SNPs,colSNPs=6:40,sep="") plotMissing(ans) # The same plot with the SNPs sorted by genomic position and # showing the information about chromosomes ans<-setupSNP(SNPs,colSNPs=6:40,sort=TRUE,SNPs.info.pos,sep="") plotMissing(ans)data(SNPs) data(SNPs.info.pos) ans<-setupSNP(SNPs,colSNPs=6:40,sep="") plotMissing(ans) # The same plot with the SNPs sorted by genomic position and # showing the information about chromosomes ans<-setupSNP(SNPs,colSNPs=6:40,sort=TRUE,SNPs.info.pos,sep="") plotMissing(ans)
This function plots ranked observed p values against the corresponding expected p values in -log scale.
qqpval(p, pch=16, col=4, ...)qqpval(p, pch=16, col=4, ...)
p |
a vector of p values |
pch |
symbol to use for points |
col |
color for points |
... |
other plot arguments |
No return value, just the plot
data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") res<-WGassociation(casco,datSNP,model=c("do","re","log-add")) # observed vs expected p values for recessive model qqpval(recessive(res))data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") res<-WGassociation(casco,datSNP,model=c("do","re","log-add")) # observed vs expected p values for recessive model qqpval(recessive(res))
Information about 9307 SNPs from the HapMap project belonging to 22 chromosomes. Information about two different population is available: European population (CEU) and Yoruba (YRI). The genomic information (names of SNPs, chromosomes and genetic position) is also available in a data frame called 'HapMap.SNPs.pos'.
data(resHapMap)data(resHapMap)
A data frame with 120 observations on the 9808 variables (SNPs) and one variable called 'group' indicating the population.
HapMap project (http://www.hapmap.org)
data(resHapMap)data(resHapMap)
This function is obsolete due to some problems with gfotran compiler. Use 'WGassociation' function instead or send an e-mail to the maintainer for receiving a version including this function
setupSNP Convert columns in a dataframe to class 'snp'
summary.setupSNP gives a summary for an object of class 'setupSNP' including
allele names, major allele frequencie, an exact thest of Hardy-Weinberg
equilibrium and percentage of missing genotypes
setupSNP(data, colSNPs, sort = FALSE, info, sep = "/", ...)setupSNP(data, colSNPs, sort = FALSE, info, sep = "/", ...)
data |
dataframe containing columns with the SNPs to be converted |
colSNPs |
Vector specifying which columns contain SNPs data |
sort |
should SNPs be sorted. Default is FALSE |
info |
if sort is TRUE a dataframe containing information about the SNPs regarding their genomic position and the gene where they are located |
sep |
character separator used to divide alleles in the genotypes |
... |
optional arguments |
a dataframe of class 'setupSNP' containing converted SNP variables. All other variables will be unchanged.
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
data(SNPs) myDat<-setupSNP(SNPs,6:40,sep="") #sorted SNPs and having genomic information data(SNPs.info.pos) myDat.o<-setupSNP(SNPs,6:40,sep="",sort=TRUE, info=SNPs.info.pos) # summary summary(myDat.o) # plot one SNP plot(myDat,which=2)data(SNPs) myDat<-setupSNP(SNPs,6:40,sep="") #sorted SNPs and having genomic information data(SNPs.info.pos) myDat.o<-setupSNP(SNPs,6:40,sep="",sort=TRUE, info=SNPs.info.pos) # summary summary(myDat.o) # plot one SNP plot(myDat,which=2)
snp creates an snp object
is returns TRUE if x is of class 'snp'
as attempts to coerce its argument into an object of class 'snp'
reorder change the reference genotype
summary gives a summary for an object of class 'snp' including genotype
and allele frequencies and an exact thest of Hardy-Weinberg
equilibrium
plot gives a summary for an object of class 'snp' including genotype
and allele frequencies and an exact thest of Hardy-Weinberg
equilibrium in a plot. Barplot or pie are allowed
[.snp is a copy of [.factor modified to preserve all attributes
snp(x, sep = "/", name.genotypes, reorder="common", remove.spaces = TRUE, allow.partial.missing = FALSE) is.snp(x) as.snp(x, ...) ## S3 method for class 'snp' additive(o)snp(x, sep = "/", name.genotypes, reorder="common", remove.spaces = TRUE, allow.partial.missing = FALSE) is.snp(x) as.snp(x, ...) ## S3 method for class 'snp' additive(o)
x |
either an object of class 'snp' or an object to be converted to class 'snp' |
sep |
character separator used to divide alleles when |
name.genotypes |
the codes for the genotypes. This argument may be useful when genotypes are coded using three different codes (e.g., 0,1,2 or hom1, het, hom2) |
reorder |
how should genotypes within an individual be reordered. Possible values are
'common' or 'minor'. The default is
|
remove.spaces |
logical indicating whether spaces and tabs will be removed from the genotypes before processing |
allow.partial.missing |
logical indicating whether one allele is permitted to be missing. When set to 'FALSE' both alleles are set to 'NA' when either is missing. |
o |
an object of class 'snp' to be coded as a linear covariate: 0,1,2 |
... |
optional arguments |
SNP objects hold information on which gene or marker alleles were observed for different individuals. For each individual, two alleles are recorded.
The snp class considers the stored alleles to be unordered , i.e., "C/T" is equivalent to "T/C". It assumes that the order of the alleles is not important.
When snp is called, x is a character vector, and it is
assumed that each element encodes both alleles. In this case, if
sep is a character string, x is assumed to be coded
as "Allele1<sep>Allele2". If sep is a numeric value, it is
assumed that character locations 1:sep contain allele 1 and
that remaining locations contain allele 2.
additive.snp recodes the SNPs for being analyzed as a linear covariate (codes 0,1,2)
The snp class extends "factor" where the levels is a character vector of possible
genotype values stored coded by paste( allele1, "", allele2, sep="/")
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
# some examples of snp data in different formats dat1 <- c("21", "21", "11", "22", "21", "22", "22", "11", "11", NA) ans1 <- snp(dat1,sep="") ans1 dat2 <- c("A/A","A/G","G/G","A/G","G/G", "A/A","A/A","G/G",NA) ans2 <- snp(dat2,sep="/") ans2 dat3 <- c("C-C","C-T","C-C","T-T","C-C", "C-C","C-C","C-C","T-T",NA) ans3 <- snp(dat3,sep="-") ans3 dat4 <- c("het","het","het","hom1","hom2", "het","het","hom1","hom1",NA) ans4 <- snp(dat4,name.genotypes=c("hom1","het","hom2")) ans4 # summary summary(ans3) # plots plot(ans3) plot(ans3,type=pie) plot(ans3,type=pie,label="SNP 10045")# some examples of snp data in different formats dat1 <- c("21", "21", "11", "22", "21", "22", "22", "11", "11", NA) ans1 <- snp(dat1,sep="") ans1 dat2 <- c("A/A","A/G","G/G","A/G","G/G", "A/A","A/A","G/G",NA) ans2 <- snp(dat2,sep="/") ans2 dat3 <- c("C-C","C-T","C-C","T-T","C-C", "C-C","C-C","C-C","T-T",NA) ans3 <- snp(dat3,sep="-") ans3 dat4 <- c("het","het","het","hom1","hom2", "het","het","hom1","hom1",NA) ans4 <- snp(dat4,name.genotypes=c("hom1","het","hom2")) ans4 # summary summary(ans3) # plots plot(ans3) plot(ans3,type=pie) plot(ans3,type=pie,label="SNP 10045")
SNPs data.frame contains selected SNPs and other clinical covariates for cases and controls in a case-control study
SNPs.info.pos data.frame contains the names of the SNPs included in the data set 'SNPs' including their chromosome and their genomic position
data(SNPs)data(SNPs)
'SNPs' data.frame contains the following columns:
| id | identifier of each subject |
| casco | case or control status: 0-control, 1-case |
| sex | gender: Male and Female |
| blood.pre | arterial blood presure |
| protein | protein levels |
| snp10001 | SNP 1 |
| snp10002 | SNP 2 |
| ... | ... |
| snp100036 | SNP 36 |
Data obtained from our department. The reference and details will be supplied after being published.
SNPs data.frame contains selected SNPs and other clinical covariates for cases and controls in a case-control study
SNPs.info.pos data.frame contains the names of the SNPs included in the data set 'SNPs' including their chromosome and their genomic position
data(SNPs.info.pos)data(SNPs.info.pos)
'SNPs.info.pos' data.frame contains the following columns: A data frame with 35 observations on the following 3 variables.
snpname of SNP
chrname of chromosome
posgenomic position
Data obtained from our department. The reference and details will be supplied after being published.
This function sorts a vector with the position of SNPs in a data frame using another data frame which contains information about SNPs, their chromosome, and their genomic position
sortSNPs(data, colSNPs, info)sortSNPs(data, colSNPs, info)
data |
a required data frame with the SNPs |
colSNPs |
a required vector indicating which columns of 'data' contains genotype data |
info |
a required data frame with genomic information for the SNPs (chromosome and position). The first column must have the SNPs, the second one the chromosome and the third one the genomic position. |
First of all, the function obtains a vector with the SNPs sorted using the data frame with the genomic positions (see 'dataSNPs.pos' argument). Then, the columns which indicate where the information about the genotypes is in our data frame, are sorted using this vector.
This information is useful when WGassociation function is called since it
allow the user to summaryze the results with the SNPs sorted by genomic position
a vector indicating the colums where the SNPs are recorded in our data frame ('data' argument), sorted using the genomic positions listed in 'dataSNPs.pos' argument)
# # data(SNPs) # data(SNPs.info.pos) # colSNPs.order<-sortSNPs(SNPs,c(6:40),SNPs.info.pos) ## # data(SNPs) # data(SNPs.info.pos) # colSNPs.order<-sortSNPs(SNPs,c(6:40),SNPs.info.pos) #
This function computes sample size, mean and standard error of a quantitative trait for each genotype (or combination of genotypes)
Table.mean.se(var, dep, subset = !is.na(var))Table.mean.se(var, dep, subset = !is.na(var))
var |
quantitative trait |
dep |
variable with genotypes or any combination of them |
subset |
an optional vector specifying a subset of observations to be used in the descriptive analysis |
tp |
A matrix giving sample size (n), median (me) and standard error (se) for each genotype |
data(SNPs) # sample size, mean age and standard error for each genotype Table.mean.se(SNPs$snp10001,SNPs$protein) # The same table for a subset (males) Table.mean.se(SNPs$snp10001,SNPs$protein,SNPs$sex=="Male") # The same table assuming a dominant model Table.mean.se(dominant(snp(SNPs$snp10001,sep="")),SNPs$protein,SNPs$sex=="Male")data(SNPs) # sample size, mean age and standard error for each genotype Table.mean.se(SNPs$snp10001,SNPs$protein) # The same table for a subset (males) Table.mean.se(SNPs$snp10001,SNPs$protein,SNPs$sex=="Male") # The same table assuming a dominant model Table.mean.se(dominant(snp(SNPs$snp10001,sep="")),SNPs$protein,SNPs$sex=="Male")
This function computes sample size and percentage for each category of a categorical trait (e.g. case-control status) for each genotype (or combination of genotypes).
Table.N.Per(var, dep, subset = !is.na(var))Table.N.Per(var, dep, subset = !is.na(var))
var |
categorical trait. |
dep |
variable with genotypes or any combination of them |
subset |
an optional vector specifying a subset of observations to be used in the descriptive analysis. |
tp |
A matrix giving sample size (n),and the percentage (%) for each level of the categorical trait for each genotype |
data(SNPs) #sample size and percentage of cases and controls for each genotype Table.N.Per(SNPs$snp10001,SNPs$casco) # The same table for a subset (males) Table.N.Per(SNPs$snp10001,SNPs$casco,SNPs$sex=="Male") # The same table assuming a dominant model Table.N.Per(dominant(snp(SNPs$snp10001,sep="")),SNPs$casco,SNPs$sex=="Male")data(SNPs) #sample size and percentage of cases and controls for each genotype Table.N.Per(SNPs$snp10001,SNPs$casco) # The same table for a subset (males) Table.N.Per(SNPs$snp10001,SNPs$casco,SNPs$sex=="Male") # The same table assuming a dominant model Table.N.Per(dominant(snp(SNPs$snp10001,sep="")),SNPs$casco,SNPs$sex=="Male")
Test the null hypothesis that Hardy-Weinberg equilibrium holds in cases, controls and both populations.
print print the information. Number of digits, and significance
level can be changed
tableHWE(x, strata, ...)tableHWE(x, strata, ...)
x |
an object of class 'setupSNP' |
strata |
a factor variable for a stratified analysis |
... |
optional arguments |
This function calculates the HWE test for those variables of class 'snp' in the object x of class 'setupSNP'
A matrix with p values for Hardy-Weinberg Equilibrium
This function is based on an R function which computes an exact SNP test of Hardy-Weinberg Equilibrium written by Wigginton JE, Cutler DJ and Abecasis GR available at http://csg.sph.umich.edu/abecasis/Exact/r_instruct.html
Wigginton JE, Cutler DJ and Abecasis GR (2005). A note on exact tests of Hardy-Weinberg equilibrium. Am J Hum Genet 76:887-93
data(SNPs) ans<-setupSNP(SNPs,6:40,sep="") res<-tableHWE(ans) print(res) #change the significance level showed in the flag column print(res,sig=0.001) #stratified analysis res<-tableHWE(ans,ans$sex) print(res)data(SNPs) ans<-setupSNP(SNPs,6:40,sep="") res<-tableHWE(ans) print(res) #change the significance level showed in the flag column print(res,sig=0.001) #stratified analysis res<-tableHWE(ans,ans$sex) print(res)
This function carries out a whole genome association analysis between the SNPs and a dependent variable (phenotype) under five different genetic models (inheritance patterns): codominant, dominant, recessive, overdominant and log-additive. The phenotype may be quantitative or categorical. In the second case (e.g. case-control studies) this variable must be of class 'factor' with two levels.
WGassociation(formula, data, model = c("all"), quantitative = is.quantitative(formula, data), genotypingRate = 80, level = 0.95, ...)WGassociation(formula, data, model = c("all"), quantitative = is.quantitative(formula, data), genotypingRate = 80, level = 0.95, ...)
formula |
either a symbolic description of the model to be fited (a formula object) without the SNP
or the name of response variable in the case of fitting single models (e.g. unadjusted models).
It might have either a continuous variable (quantitative traits) or a
factor variable (case-control studies) as the response on the left of the |
data |
a required dataframe of class 'setupSNP' containing the variables in the model and the SNPs |
model |
a character string specifying the type of genetic model (mode of inheritance) for the SNP. This indicates how the genotypes should be collapsed. Possible values are "codominant", "dominant", "recessive", "overdominant", "log-additive" or "all". The default is "all" that fits the 5 possible genetic models. Only the first words are required, e.g "co", "do", etc. |
quantitative |
logical value indicating whether the phenotype (that which is in the left of the operator ~ in 'formula' argument) is quantitative. The function 'is.quantitative' returns FALSE when the phenotype is a variable with two categories (i.e. indicating case-control status). Thus, it is not a required argument but it may be modified by the user. |
genotypingRate |
minimum percentage of genotype rate for a given SNP to be included in the analysis. Default is 80%. |
level |
signification level for confidence intervals. Defaul 95%. |
... |
Other arguments to be passed through glm function |
This function assesses the association between the response variable included in the left side in the 'formula' and the SNPs included in the 'data' argument adjusted by those variables included in the right side of the 'formula'. Different genetic models may be analyzed using 'model' argument.
An object of class 'WGassociation'.
'summary' returns a summary table by groups defined in info (genes/chromosomes).
'WGstats' returns a detailed output, similar to the produced by association.
'pvalues' and 'print' return a table of p-values for each genetic model for each SNP. The first column indicates whether a problem with genotyping is present.
'plot' produces a plot of p values in the -log scale. See plot.WGassociation for
further details.
'labels' returns the names of the SNPs analyzed.
The functions 'codominat', 'dominant', 'recessive', 'overdominant' and 'additive' are used to obtain the p values under these genetic models.
See examples for further illustration about all previous issues.
JR Gonzalez, L Armengol, X Sole, E Guino, JM Mercader, X Estivill, V Moreno. SNPassoc: an R package to perform whole genome association studies. Bioinformatics, 2007;23(5):654-5.
getSignificantSNPs association
WGstats setupSNP
plot.WGassociation
data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ansAll<-WGassociation(protein~1,data=datSNP,model="all") # In that case the formula is not required. You can also write: # ansAll<-WGassociation(protein,data=datSNP,model="all") #only codominant and log-additive ansCoAd<-WGassociation(protein~1,data=datSNP,model=c("co","log-add")) #for printing p values print(ansAll) print(ansCoAd) #for obtaining a matrix with the p palues pvalAll<-pvalues(ansAll) pvalCoAd<-pvalues(ansCoAd) # when all models are fitted and we are interested in obtaining # p values for different genetic models # codominant model pvalCod<-codominant(ansAll) # recessive model pvalRec<-recessive(ansAll) # and the same for additive, dominant or overdominant #summary summary(ansAll) #for a detailed report WGstats(ansAll) #for plotting the p values plot(ansAll)data(SNPs) datSNP<-setupSNP(SNPs,6:40,sep="") ansAll<-WGassociation(protein~1,data=datSNP,model="all") # In that case the formula is not required. You can also write: # ansAll<-WGassociation(protein,data=datSNP,model="all") #only codominant and log-additive ansCoAd<-WGassociation(protein~1,data=datSNP,model=c("co","log-add")) #for printing p values print(ansAll) print(ansCoAd) #for obtaining a matrix with the p palues pvalAll<-pvalues(ansAll) pvalCoAd<-pvalues(ansCoAd) # when all models are fitted and we are interested in obtaining # p values for different genetic models # codominant model pvalCod<-codominant(ansAll) # recessive model pvalRec<-recessive(ansAll) # and the same for additive, dominant or overdominant #summary summary(ansAll) #for a detailed report WGstats(ansAll) #for plotting the p values plot(ansAll)