A clan is similar to the mafia family,
Clan name= origional family name
A number of families=a clan
clans are also know as Famlies, other families can become assosiates of the clan by marrying into it but they will never be members or 'family' because you have to be related by blood, clan or family members can be members of a gang structure
but the family always comes first, membership of gangs also leads to links or ties between clans.
my mothers mother is the head of the clan because she is decended from the origional founder by blood, this means that i am a member of the family, i am also a 'pure blood member' because i am directly decended from the origional founder, although my father is loved by all in the family, he will never be more than an assosiate because he is not blood related to the clan.