Navajo
Navajo culture has clans.  Sons and daughters are in the same clan their mother is in.  When meeting a new person, a Navajo will usually say their own clan and their father's clan.  Navajo culture does not allow people to marry other people from the same clan.  Navajo people usually think of anyone from the same clan as a brother, sister or cousin.  Originally, there were four Navajo clans, but there are more now.