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 and
Loss of strand specificity (i.e., reads mapping to both strands)
For more information on gDNA contamination and DNAse treatment, please, check also our RNA LEXICON Chapter #5.