Phylip format variant Relaxed PHYLIP Interleaved PHYLIP Interleaved format 1.20 It differs from Phylip Format (format_1997) on length of the ID sequence. There no length restrictions on the ID, but whitespaces aren't allowed in the sequence ID/Name because one space separates the longest ID and the beginning of the sequence. Sequences IDs must be padded to the longest ID length. Phylip multiple alignment sequence format, less stringent than PHYLIP format.