In single-cell RNA-seq. if I have to assign marker genes to a specific cell type. To do so- That marker gene will be present only in one cluster of one cell type and not any other cell type? Do we see the relative expression of marker genes and if that gene is upregulated in one cluster, that may be the case if gene is present in more than one cell type. In that case we cannot assign that particular gene as a marker gene for that particular cell. Is there any standard benchmark in this direction? Any feedback