BARCOD

BARCOD encodes multiple sequence alignments by representing insertion and deletion (indel) events as characters to preserve indel information for phylogenetic reconstruction.

Key Features:

• Encoding Indels as Single Events: BARCOD encodes each insertion or deletion event as a single character occurrence regardless of the number of nucleotides involved.
• Retention of Shared Characters: Any indel present in two or more taxa is retained as a potentially shared character for downstream phylogenetic analysis.
• Handling Complex Zones with Internested Indels and Substitutions: BARCOD codes regions containing internested insertions, deletions, and substitutions to preserve phylogenetic signal within complex alignment zones.
• Use of Methodological Codes: Alignment matrices produced by BARCOD use question marks ("?") to represent hierarchical character states rather than missing data.

Scientific Applications:

• Molecular phylogenetics: Encoding indels as characters supports reconstruction of evolutionary relationships from sequence alignments.
• Parsimony-based tree reconstruction: Encoded indel characters can be used in parsimony procedures to build cladograms.
• Homology versus homoplasy discrimination: Retained shared indels aid distinction between homologous and convergent events.
• Localization of evolutionary events: Encoded indel states help localize insertion and deletion events within inferred phylogenetic trees.

Methodology:

Encode each indel as a single character occurrence; retain indels shared by two or more taxa; code internested indels and substitutions in complex zones; use "?" in alignment matrices to denote hierarchical character states.