Figure 1

Paired-end cleaning strategy. Reads having no linker (a) are retained as single reads. If multiple linkers are present (b) in the same read, the read is discarded. In cases where the linker is partially found, meaning that the number of mismatches is lower than a threshold, only reads where the linker is located at the beginning or at the end (c) are saved as single reads, others (d) are deleted. Reads where the entire linker is present and not to closely located to one end (e) are saved as paired-end reads. In other cases, sequences are saved as single reads only if the linker is located far enough from one end (g), while others (f) are deleted.