Helps you finding candidates for alignment preservation.
Normally people have inserted new gaps in one of the two databases. ARB Merge tries to adapt the alignment.
To be able to do this, you have to specify one or more species or SAIs existing in BOTH databases. ARB Merge then creates a column reference list and realigns all transferred species according to this list.
Press the 'Find candidates' button to search both databases for candidate species/SAIs and rate them.
A list of species/SAIs shows up. The first column contains the name, the second column the number of alignments containing data for this species/SAI, the third column shows the position-count-difference (see below), the fourth column is the score (higher value means better).
The list is sorted by score, i.e. best candidates are listed at the top.
The term 'position-count-difference' is calculated like follows: For all alignments the number of non-gaps (i.e. neither '-' nor '.') are counted and the differences between these counts are summarized for all alignments. Best value is 0, which normally means the sequence data of the species (or the SAI data) didn't change. A high value means that species changed data and isn't a good candidate for alignment preservation.
To enable this feature, enable the 'Adapt alignment' toggle.