GWA(rrBLUP)
GWA()所属R语言包:rrBLUP
Genome-wide association analysis
全基因组关联分析
译者:生物统计家园网 机器人LoveR
描述----------Description----------
Performs genome-wide association analysis based on the mixed model
混合模型的基础上,进行全基因组关联分析
where β is a vector of fixed effects that can model both environmental factors and population structure. The variable g models the genetic background of each line as a random effect with Var[g] = A σ^2_A, where A is the additive relationship matrix. The residual variance is Var[\varepsilon] = I σ_e^2.
β是固定的效果,可以模拟环境因素和人口结构的向量。变量g作为随机效应模型的遗传背景,每行Var[g] = A σ^2_A,其中一个是加关系矩阵。的残余的方差是Var[\varepsilon] = I σ_e^2。
用法----------Usage----------
GWA(y, G, Z=NULL, X=NULL, min.MAF=0.05, n.core=1, check.rank=FALSE)
参数----------Arguments----------
参数:y
Vector (n \times 1) of observations. Missing values (NA) are omitted.
观测向量(n \times 1)。缺失值(NA)被省略。
参数:G
Matrix (t \times m) of genotypes for t lines with m bi-allelic markers. Genotypes should be coded as {-1,0,1} = {aa,Aa,AA}. Fractional (imputed) and missing (NA) values are allowed.
矩阵(t \times m)t行m双等位基因标记的基因型。应该被编码为{-1,0,1} = {AA,AA,AA基因型。分数(虚拟)和缺失(NA)值是允许的。
参数:Z
0-1 matrix (n \times t) relating observations to lines. If not passed, the identity matrix is used.
0-1矩阵(n \times t)观测到线。如果不通过,恒等矩阵被使用。
参数:X
Design matrix (n \times p) for the fixed effects. If not passed, a vector of 1's is used to model the intercept.
设计矩阵(n \times p)的固定效果。如果不通过,一个向量的1的用于建模的截距。
参数:min.MAF
Specifies the minimum minor allele frequency (MAF). If a marker has a MAF less than min.MAF, it is assigned a zero score.
指定的最小次要等位基因频率(MAF)。如果一个标记有MAF小于min.MAF,它被赋予一个零分。
参数:n.core
For Mac, Linux, and UNIX users, setting n.core > 1 will enable parallel execution on a machine with multiple cores. R package multicore must be installed for this to work. Do not run multicore from within the R GUI; you must use the command line.
在Mac,Linux,和UNIX用户,设置n.core> 1,使多核心的机器上并行执行。 R封装的多核必须安装这个工作。不要在R GUI运行多核,你必须使用命令行。
参数:check.rank
If TRUE, function will check the rank of the augmented design matrix for each marker. Markers for which the design matrix is singular are assigned a zero score.
如果是TRUE,函数将检查每个标记的增强设计矩阵的秩。标记的设计矩阵是奇异的,都分配了一个零分。
Details
详细信息----------Details----------
This function implements the iterative, generalized least-squares method of Kang et al. (2010), using mixed.solve for variance component estimation.
此功能实现的迭代,广义最小二乘法康等。 (2010年),使用mixed.solve方差分量估计。
The use of a minimum MAF is typically adequate to ensure the problem is well-posed. However, if an error message indicates the problem is singular, set check.rank to TRUE. This will slow down the algorithm but should fix the error.
通常是足够的,以确保使用最小的MAF问题提出。但是,如果错误信息显示的问题是奇异的,设置为TRUE check.rank。这会减慢算法,但修复的错误。
值----------Value----------
Returns m \times 1 vector of the marker scores, which equal -log_{10}(p-value)
返回m \times 1向量的标记分数,等于-log_{10}(对值)
参考文献----------References----------
Nat. Genet. 42:348-354.
实例----------Examples----------
#random population of 200 lines with 1000 markers[随机人口200线1000标记]
G <- matrix(rep(0,200*1000),200,1000)
for (i in 1:200) {
G[i,] <- ifelse(runif(1000)<0.5,-1,1)
}
QTL <- 100*(1:5) #pick 5 QTL[挑5个QTL]
u <- rep(0,1000) #marker effects[标记效应]
u[QTL] <- 1
g <- as.vector(crossprod(t(G),u))
h2 <- 0.5
y <- g + rnorm(200,mean=0,sd=sqrt((1-h2)/h2*var(g)))
scores <- GWA(y=y,G=G)
转载请注明:出自 生物统计家园网(http://www.biostatistic.net)。
注:
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