This function create a plot in which genes are plotted with respect to total counts UMI for each cell.
genesUmi(file, umiXgene = 3, sep)
a character string indicating the path of the file tab delimited of cells un-normalized expression counts.
a integer defining how many UMI are required to call a gene as present. default: 3
separator used in count file, e.g. '\t', ','
pdf with the cells counts distributions: genes.umi.pdf