my colleague sequenced (RNA-Seq) some samples a month ago and the quality of some of them was not so good. She sequenced some new samples and also some of the bad quality samples again to analyze them again. She is asking me if, in order to have more reads and better results, I can re-use the bad quality old reads (.fastq files) and merge them with the new ones (only with the samples that have been re sequenced). Is this possible? Is it recommended or bad practice? It does not sound very good to me, but I don't have experience with this.
If it is a good idea, should I do it with command 'cat' or how? thank you.