Questions about nested Hierarchy

[Paraleptopecten (Timothy Campbell)]

@RichardG

The DNA will match, of course it will match.

In what fashion is this not valid?

@Paraleptopecten

Nearly all members (that have been checked) of Buccinoidea, Muricidae, Olivoidea, “Turbinelloidea”, and Conoidea share TTTACTGGT GC GTCGGCTGCGAGCGT in the earlier part of their 28S genes. Most other caenogastropods have a CG instead of the bold GC.

The gene is producing part of nuclear ribosomes in pretty much all animals. Why does that change only appear in a large subset of gastropods that also share a siphon, fairly frequent large size, have similar radular morphologies, and are macrocarnivors (except for columbellids), if they are not actually related?