Differential expression analysis based on the Negative Binomial distribution using DESeq2.
run_deseq2(
ps,
group,
confounders = character(0),
contrast = NULL,
taxa_rank = "all",
norm = "RLE",
norm_para = list(),
transform = c("identity", "log10", "log10p"),
fitType = c("parametric", "local", "mean", "glmGamPoi"),
sfType = "poscounts",
betaPrior = FALSE,
modelMatrixType,
useT = FALSE,
minmu = ifelse(fitType == "glmGamPoi", 1e-06, 0.5),
p_adjust = c("none", "fdr", "bonferroni", "holm", "hochberg", "hommel", "BH", "BY"),
pvalue_cutoff = 0.05,
...
)
a phyloseq::phyloseq
object.
character, the variable to set the group, must be one of the var of the sample metadata.
character vector, the confounding variables to be adjusted.
default character(0)
, indicating no confounding variable.
this parameter only used for two groups comparison while there are multiple groups. For more please see the following details.
character to specify taxonomic rank to perform
differential analysis on. Should be one of
phyloseq::rank_names(phyloseq)
, or "all" means to summarize the taxa by
the top taxa ranks (summarize_taxa(ps, level = rank_names(ps)[1])
), or
"none" means perform differential analysis on the original taxa
(taxa_names(phyloseq)
, e.g., OTU or ASV).
the methods used to normalize the microbial abundance data. See
normalize()
for more details.
Options include:
"none": do not normalize.
"rarefy": random subsampling counts to the smallest library size in the data set.
"TMM": trimmed mean of m-values. First, a sample is chosen as reference. The scaling factor is then derived using a weighted trimmed mean over the differences of the log-transformed gene-count fold-change between the sample and the reference.
"RLE", relative log expression, RLE uses a pseudo-reference calculated using the geometric mean of the gene-specific abundances over all samples. The scaling factors are then calculated as the median of the gene counts ratios between the samples and the reference.
"CSS": cumulative sum scaling, calculates scaling factors as the cumulative sum of gene abundances up to a data-derived threshold.
arguments passed to specific normalization methods. Most users will not need to pass any additional arguments here.
character, the methods used to transform the microbial
abundance. See transform_abundances()
for more details. The
options include:
"identity", return the original data without any transformation (default).
"log10", the transformation is log10(object)
, and if the data contains
zeros the transformation is log10(1 + object)
.
"log10p", the transformation is log10(1 + object)
.
these seven
parameters are inherited form DESeq2::DESeq()
.
fitType
, either "parametric", "local", "mean", or "glmGamPoi" for the
type of fitting of dispersions to the mean intensity.
sfType
, either "ratio", "poscounts", or "iterate" for the type of size
factor estimation. We recommend to use "poscounts".
betaPrior
, whether or not to put a zero-mean normal prior on the
non-intercept coefficients.
modelMatrixType
, either "standard" or "expanded", which describe how
the model matrix,
useT
, logical, where Wald statistics are assumed to follow a standard
Normal.
minmu
, lower bound on the estimated count for fitting gene-wise
dispersion.
For more details, see DESeq2::DESeq()
. Most users will not need to
set this arguments (just use the defaults).
method for multiple test correction, default none
, for
more details see stats::p.adjust.
pvalue_cutoff numeric, p value cutoff, default 0.05.
extra parameters passed to DESeq2::DESeq()
.
a microbiomeMarker
object.
Note: DESeq2 requires the input is raw counts (un-normalized counts), as
only the counts values allow assessing the measurement precision correctly.
For more details see the vignette of DESeq2 (vignette("DESeq2")
).
Thus, this function only supports "none", "rarefy", "RLE", "CSS", and "TMM" normalization methods. We strongly recommend using the "RLE" method (default normalization method in the DESeq2 package). The other normalization methods are used for expert users and comparisons among different normalization methods.
For two groups comparison, this function utilizes the Wald test (defined by
DESeq2::nbinomWaldTest()
) for hypothesis testing. A Wald test statistic
is computed along with a probability (p-value) that a test statistic at least
as extreme as the observed value were selected at random. contrasts
are
used to specify which two groups to compare. The order of the names
determines the direction of fold change that is reported.
Likelihood ratio test (LRT) is used to identify the genes that significantly changed across all the different levels for multiple groups comparisons. The LRT identified the significant features by comparing the full model to the reduced model. It is testing whether a feature removed in the reduced model explains a significant variation in the data.
contrast
must be a two length character or NULL
(default). It is only
required to set manually for two groups comparison when there are multiple
groups. The order determines the direction of comparison, the first element
is used to specify the reference group (control). This means that, the first
element is the denominator for the fold change, and the second element is
used as baseline (numerator for fold change). Otherwise, users do required
to concern this parameter (set as default NULL
), and if there are
two groups, the first level of groups will set as the reference group; if
there are multiple groups, it will perform an ANOVA-like testing to find
markers which difference in any of the groups.
Love, Michael I., Wolfgang Huber, and Simon Anders. "Moderated estimation of fold change and dispersion for RNA-seq data with DESeq2." Genome biology 15.12 (2014): 1-21.
data(enterotypes_arumugam)
ps <- phyloseq::subset_samples(
enterotypes_arumugam,
Enterotype %in% c("Enterotype 3", "Enterotype 2")) %>%
phyloseq::subset_taxa(Phylum %in% c("Firmicutes"))
run_deseq2(ps, group = "Enterotype")
#> Warning: Some counts are non-integers, they are rounded to integers.
#> Raw count is recommended for reliable results for deseq2 method.
#> converting counts to integer mode
#> microbiomeMarker-class inherited from phyloseq-class
#> normalization method: [ RLE ]
#> microbiome marker identity method: [ DESeq2: Wald ]
#> marker_table() Marker Table: [ 6 microbiome markers with 5 variables ]
#> otu_table() OTU Table: [ 78 taxa and 24 samples ]
#> sample_data() Sample Data: [ 24 samples by 10 sample variables ]
#> tax_table() Taxonomy Table: [ 78 taxa by 1 taxonomic ranks ]