What are Clan Marks?

[LillyWandsworth]

It's either genetic and appear as a person ages or they paint them on when they are old enough, because neither T'kebbe or Khloe or any other miqo'te child have them.

The U tribe in Forgotten Springs all have the same clan mark but in different stages some only have one line while others have 2 or even 3 this could be a genetic thing as the younger ones seem to have less stripes, but also could be made to denote rank or status.

As for the first a lot of miqo'te don't have marks, and I wonder is this due to the destruction of clan lines so no one bothers to put clan marks on because they don't know what they look like or there not enough miqo'te left after the flood that 200 years of reproduction with other races have meant that those genetic markers have been lost?

Ideas welcomed.