Function to estimate the copy number profile with a piecewise constant function using mBPCR. Eventually, it is possible to estimate the profile with a
smoothing curve using either the Bayesian Regression Curve with K_2 (BRC with K_2) or the Bayesian Regression Curve Averaging over k (BRCAk). It is also possible
to choose the estimator of the variance of the levels rhoSquare (i.e. either hat{ρ}_1^2 or hat{ρ}^2) and by default hat{ρ}_1^2 is used.
array containing the log2ratio of the copy number data
kMax
maximum number of segments
nu
mean of the segment levels. If nu=NULL, then the algorithm estimates it on the sample.
rhoSquare
variance of the segment levels. If rhoSquare=NULL, then the algorithm estimates it on the sample.
sigmaSquare
variance of the noise. If sigmaSquare=NULL, then the algorithm estimates it on the sample.
typeEstRho
choice of the estimator of rhoSquare. If typeEstRho=1, then the algorithm estimates rhoSquare
with hat{ρ}_1^2, while if typeEstRho=0, it estimates rhoSquare with hat{ρ}^2.
regr
choice of the computation of the regression curve. If regr=NULL, then the regression curve is not computed,
if regr="BRC" the Bayesian Regression Curve with K_2 is computed (BRC with K_2), if regr="BRCAk" the Bayesian
Regression Curve Averaging over k is computed (BRCAk).
Details
By default, the function estimates the copy number profile with mBPCR and estimating rhoSquare on the sample, using hat{ρ}_1^2. It is
also possible to use hat{ρ}^2 as estimator of rhoSquare, by setting typeEstRho=0, or to directly set the value of the parameter.
The function gives also the possibility to estimate the profile with a Bayesian regression curve: if regr="BRC" the Bayesian Regression Curve with K_2 is computed (BRC with K_2), if regr="BRCAk" the Bayesian
Regression Curve Averaging over k is computed (BRCAk).
Value
A list containing:
estK
the estimated number of segments
estBoundaries
the estimated boundaries
estPC
the estimated profile with mBPCR
regrCurve
the estimated bayesian regression curve. It is returned only if regr!=NULL.
nu
rhoSquare
sigmaSquare
postProbT
for each probe, the posterior probablity to be a breakpoint
References
Rancoita, P. M. V., Hutter, M., Bertoni, F., Kwee, I. (2009).
Bayesian DNA copy number analysis. BMC Bioinformatics 10: 10.
http://www.idsia.ch/~paola/mBPCR
##import the 250K NSP data of chromosome 11 of cell line JEKO-1
data(jekoChr11Array250Knsp)
##first example
## we select a part of chromosome 11
y <- jekoChr11Array250Knsp$log2ratio[6400:6900]
p <- jekoChr11Array250Knsp$PhysicalPosition[6400:6900]
##we estimate the profile using the global parameters estimated on the whole genome
##the profile is estimated with mBPCR and with the Bayesian Regression Curve
results <- computeMBPCR(y, nu=-3.012772e-10, rhoSquare=0.0479, sigmaSquare=0.0699, regr="BRC")
plot(p, y)
points(p, results$estPC, type='l', col='red')
points(p, results$regrCurve,type='l', col='green')
###second example
### we select a part of chromosome 11
#y <- jekoChr11Array250Knsp$log2ratio[10600:11600]
#p <- jekoChr11Array250Knsp$PhysicalPosition[10600:11600]
###we estimate the profile using the global parameters estimated on the whole genome
###the profile is estimated with mBPCR and with the Bayesian Regression Curve Ak
#results <- computeMBPCR(y, nu=-3.012772e-10, rhoSquare=0.0479, sigmaSquare=0.0699, regr="BRCAk")
#plot(p,y)
#points(p, results$estPC, type='l', col='red')
#points(p, results$regrCurve, type='l', col='green')
Results
R version 3.3.1 (2016-06-21) -- "Bug in Your Hair"
Copyright (C) 2016 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)
R is free software and comes with ABSOLUTELY NO WARRANTY.
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Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> library(mBPCR)
Loading required package: oligoClasses
Welcome to oligoClasses version 1.34.0
Loading required package: SNPchip
Welcome to SNPchip version 2.18.0
> png(filename="/home/ddbj/snapshot/RGM3/R_BC/result/mBPCR/computeMBPCR.Rd_%03d_medium.png", width=480, height=480)
> ### Name: computeMBPCR
> ### Title: Estimate the copy number profile
> ### Aliases: computeMBPCR
> ### Keywords: regression smooth
>
> ### ** Examples
>
> ##import the 250K NSP data of chromosome 11 of cell line JEKO-1
> data(jekoChr11Array250Knsp)
>
>
> ##first example
> ## we select a part of chromosome 11
> y <- jekoChr11Array250Knsp$log2ratio[6400:6900]
> p <- jekoChr11Array250Knsp$PhysicalPosition[6400:6900]
> ##we estimate the profile using the global parameters estimated on the whole genome
> ##the profile is estimated with mBPCR and with the Bayesian Regression Curve
> results <- computeMBPCR(y, nu=-3.012772e-10, rhoSquare=0.0479, sigmaSquare=0.0699, regr="BRC")
Computation of log(A^0)
Computation of left and right recursions
Determination of PC Regression
Computation of Bayesian regression Curve
> plot(p, y)
> points(p, results$estPC, type='l', col='red')
> points(p, results$regrCurve,type='l', col='green')
>
> ###second example
> ### we select a part of chromosome 11
> #y <- jekoChr11Array250Knsp$log2ratio[10600:11600]
> #p <- jekoChr11Array250Knsp$PhysicalPosition[10600:11600]
> ###we estimate the profile using the global parameters estimated on the whole genome
> ###the profile is estimated with mBPCR and with the Bayesian Regression Curve Ak
> #results <- computeMBPCR(y, nu=-3.012772e-10, rhoSquare=0.0479, sigmaSquare=0.0699, regr="BRCAk")
> #plot(p,y)
> #points(p, results$estPC, type='l', col='red')
> #points(p, results$regrCurve, type='l', col='green')
>
>
>
>
>
>
> dev.off()
null device
1
>