A bubble is also formed when an error occurs during the sequence reading process; however, wherever the error happens, there is a path for the k-mer reads to reconnect with the main graph and continue as though nothing had ever happened. When there are tips and bubbles present in a de Bruijn graph formed from the data, they may be removed only if an error is what caused the tip or bubble to appear. When scientists are using a reference genome, they can quickly and easily tell where tips are located by comparing the graph of the reference genome and the graph of the sequence.