Invalid or prohibited marriages.

(a) The following marriages are prohibited: (1) A marriage entered into prior to the dissolution of an earlier marriage of one of the parties; (2) A marriage between an ancestor and a descendant, or between a brother and a sister, whether the relationship is by the half or the whole blood; (3) A marriage between an aunt and a nephew or between an uncle and a niece, whether the relationship is by the half or the whole blood, except as to marriages permitted by established tribal custom; (4) A marriage prohibited by custom and usage of the tribe. (b) Children born of a prohibited marriage are legitimate.