Miss. Code Ann. § 25-9-105

It is the intent of this chapter to consolidate into one (1) state personnel system all agencies and employees now administered by the Mississippi Classification Commission, agencies and employees now administered by the Mississippi Coordinated Merit System Council, and such other agencies and employees except as excluded by this chapter. The State Personnel Board established herein shall assume the total functions of personnel administration services (a) for those agencies and positions now required and operating under merit system rules due to federal statutory and regulatory provisions or state law, and (b) for all state agencies, departments and institutions except as excluded by this chapter. However, state agencies which are not required by law to operate under merit system rules may request an exemption from the applicant selection process by specific job class or on an agency-wide basis when such exemption is justifiable.