I have a set of genes where I want to check whether these genes are transcribed in different individuals (from the same species ) or not. I have the RNA-seq data where total mRNA was pooled from different tissues (without any replicates). By checking the coverage of different genes from this data, how correctly I will be able to tell whether a gene is transcribed or not? And what further experiments can confirm this? What should be the threshold for no-coverage (like 0 read-coverage or I should be bit relaxed) ?