72-3-310. Burdens in contested cases. In contested cases, petitioners who seek to establish intestacy have the burden of establishing prima facie proof of death, venue, and heirship. Proponents of a will have the burden of establishing prima facie proof of due execution in all cases and, if they are also petitioners, prima facie proof of death and venue. Contestants of a will have the burden of establishing lack of testamentary intent or capacity, undue influence, fraud, duress, mistake, or revocation. Parties have the ultimate burden of persuasion as to matters with respect to which they have the initial burden of proof.