What important function does Jocasta play in the play Oedipus Rex other than being the mother/wife of Oedipus?

In Oedipus Rex, Jocasta plays the
following roles:

Peacemaker:
she intercedes between Oedipus and Creon, trying to get the men to calm down, no doubt a
testament to her mother-figure
role.

Foil: she is a
reflection of Oedipus.  She triggers his memory and figures out the mystery of Lauis'
murder sooner than he does.  As such, she is a part of the way the dramatic irony
functions.

Supplient: one who
provides vision and unmitigated suffering and helplessness.  She suffers only briefly in
the tragedy, killing herself almost as soon as she realizes her crimes of murder and
incest.

Not a tragic hero:
Notice that she kills herself and Oedipus does not.  Why?  Her crimes were pre-meditated
and more cruel: she tried to commit infanticide.  Because of her suicide, Oedipus blinds
himself with her pins, but he decides--unlike her--to take responsibility for his
crimes.  Thus, he becomes a tragic hero.  She does not deserve the title because of her
cruelty and lack of responsibility.