Miss. Code § 91-5-29
In case the wife have a separate property at the time of the death of her husband, equal in value to what would be her lawful portion of her husband's real and personal estate, and he have made a will, she shall not be at liberty to signify her dissent to the will or to renounce any provision or bequest therein in her favor and elect to take her portion of his estate. If her separate property be not equal in value to what would be the value of her portion of her husband's estate, then she may signify her dissent to the will, as in other cases provided by law, and claim to have the deficiency made up to her, notwithstanding the will. The court in which the will is probated may appoint three commissioners to ascertain, by valuation of the estate, what her lawful portion thereof would be worth; and the commissioners shall also value her own separate estate and report their valuation to the court. Whereupon the court shall make the proper order for allowing her to share in her husband's real and personal estate to make up the deficiency after the following rule: if her separate property be equal in value to two thirds of what she would be entitled to, she shall have one third of her lawful portion of the land and one third of what would be her distributive share of the personalty; if her separate property be worth half in value what she would be entitled to, then she shall be entitled to half her lawful portion of real estate and half of what would be her distributive share of the personalty; if her separate property be worth only one third in value what she would be entitled to, then she shall be entitled to two thirds of her lawful portion of real estate and two thirds of what would be her distributive share in the personalty. This section shall not preclude or prevent any married woman from renouncing the provisions of her husband's will and electing to take her lawful portion if her separate property do not amount in value to one fifth of what she would be entitled to. This section shall apply to a husband renouncing the will of his wife, and shall govern as to his right to share in her estate in such case.
Miss. Code § 91-5-29