How to define a 'HGT gene'?

Microbial community profiling WAAFLE
1

I’m trying to understand how to identify an HGT gene. If ‘B’ is the HGT gene in a contig like ‘AAAB’, and ‘A’ is the HGT gene in ‘ABBB’, then what about ‘AB’, ‘AAABB’? Is the gene in the minority always the HGT one? When the quantities of A and B are equal, which one is the HGT gene?

2

What about a ‘ABBBBBBBBA‘ contig? Is the HGT gene “A“ or “B“?