singleMarkerRegression: Run a single marker regression using marker dosages

In polyqtlR: QTL Analysis in Autopolyploid Bi-Parental F1 Populations

Description

Function to run a single marker regression using marker dosages

Usage

singleMarkerRegression(
  dosage_matrix,
  Phenotype.df,
  genotype.ID,
  trait.ID,
  maplist = NULL,
  perm_test = FALSE,
  N_perm = 1000,
  alpha = 0.05,
  ncores = 1,
  return_R2 = FALSE,
  log = NULL
)

Arguments

dosage_matrix	An integer matrix with markers in rows and individuals in columns. All markers in this matrix will be tested for association with the trait.
Phenotype.df	A data.frame containing phenotypic values
genotype.ID	The colname of Phenotype.df that contains the population identifiers (F1 names) (must be a colname of Phenotype.df)
trait.ID	The colname of Phenotype.df that contains the response variable to use in the model (must be a colname of Phenotype.df)
maplist	Option to include linkage map in the format returned by MDSMap_from_list from polymapR. If maplist is not specified (by default NULL) then no ordering of markers from dosage-matrix is performed. Note that all markers in dosage_matrix are tested; markers with dosages that were not on the maplist will be assigned unordered to linkage group 0 with dummy cM positions 1,2,3 etc.
perm_test	Logical, by default FALSE. If TRUE, a permutation test will be performed to determine a genome-wide significance threshold.
N_perm	Integer. The number of permutations to run if perm_test is TRUE; by default this is 1000.
alpha	Numeric. The P-value to be used in the selection of a threshold if perm_test is TRUE; by default 0.05 (i.e. the 0.95 quantile).
ncores	Number of cores to use if parallel processing required. Works both for Windows and UNIX (using doParallel). Use parallel::detectCores() to find out how many cores you have available.
return_R2	Should the (adjusted) R2 of the model fit also be determined?
log	Character string specifying the log filename to which standard output should be written. If NULL log is send to stdout.

Value

A list containing the following components:

• QTL.res : The -log(p) of the model fit per marker are returned as "LOD" scores, although "LOP" would have been a better description. If requested, R2 values are also returned in column "R2adj"

• Perm.res : The results of the permutation test if performed, otherwise NULL

• Map : The linkage map if provided, otherwise NULL

Examples

data("SNP_dosages.4x","BLUEs.pheno")
Trait_1.smr <- singleMarkerRegression(dosage_matrix = SNP_dosages.4x,
Phenotype.df = BLUEs.pheno,genotype.ID = "Geno",trait.ID = "BLUE")

polyqtlR documentation built on Feb. 2, 2022, 5:09 p.m.