either a matrix of exon-level counts or a DGEList object with (at least) elements counts (table of counts summarized at the exon level) and samples (data frame containing information about experimental group, library size and normalization factor for the library size). Each row of y should represent one exon.

vector of length equal to the number of rows of y, which provides the gene identifier for each exon in y. These identifiers are used to group the relevant exons into genes for the gene-level analysis of splice variation.

factor supplying the experimental group/condition to which each sample (column of y) belongs. If NULL (default) the function will try to extract if from y, which only works if y is a DGEList object.