Yes, they are sisters. I know, it's weird because they don't look the same and their behivour is so different from each other.
I shouldn't say this (I hope Dunga won't read Cat Forum today) but sometimes we make fun of Dunga's white chin. Sometimes we call her "white chin". It's just funny how she has it white. There is no other part of her body white!
Oliver looks like her...I noticed some time ago. Dunga can't beat Oliver though....NOONE can sit like Oliver! He has a unique sitting position. LOL Is Oliver loud? Dunga is VERY loud cat.