why do intersect before runharmony ?

[GGanakin]

In scCombination.R .

        share.genes <- Reduce(intersect,  lapply(expr.list, rownames))
        for(s.name in names(expr.list)){
            expr.list[[s.name]] <- GetAssayData(expr.list[[s.name]], slot = "counts")[share.genes, ]
        }

This resulted in the removal of some of the gene expression, but was not advised to do so on the official Harmony website