Most eukaryotic parasites have small genome (in MBs maximum size is 300-400 MB) but there are few eukaryotic parasites like liver fluke- Fasciola hepatica that have more than 1 GB size.
How can this paradox be explained, as this size cannot be explained by genome duplication or expansion of a single repeat element.
Paper related with huge size of F. hepatica is attached for reference.
Please suggest the possibilities.