try schex and/or Nebulosa packages for addressing overplotting: actually, we don't think that they'll be helpful for this scenario
Make 10 paired plots: one per donor, and color per region each pair. This will reduce overplotting and also show the donor effects. You could arrange them into 4 columns and 5 rows (donors on rows)
Optional
schex
and/orNebulosa
packages for addressing overplotting: actually, we don't think that they'll be helpful for this scenarioregion
each pair. This will reduce overplotting and also show the donor effects. You could arrange them into 4 columns and 5 rows (donors on rows)