a data matrix or a data frame if `PCAdapt = FALSE`.
res
a list of quantities among which are the loadings.
method
a character string that specifies the method used to compute the p-values.
nSNP
an integer specifying the number of genetic markers.
K
an integer specifying the number of principal components to retain.
data.type
a character string that specifies the type of data being read, either a genotype matrix (data.type="genotype"),
or a matrix of allele frequencies (data.type="pool", or outputs from the software PCAdapt (data.t
min.maf
a value between 0 and 0.5 specifying the threshold of minor allele frequencies above which p-values are computed.