The presence of gDNA contamination can strongly impact the sequencing data and lead to biases and quantification issues during data analysis.
A typical signature of gDNA contamination includes:
A high proportion of intronic and intergenic reads
Loss of strand specificity (i.e., reads mapping to both strands)
For NOTE: for more information on gDNA contamination and DNAse treatment, please, check our RNA LEXICON Chapter #5.