This episode's headline: Lifting Sanctions; Gene Marker. The guests include DUMISANI KUMALO, Anti-Apartheid Activist; MICHAEL CHRISTIE, South Africa Foundation; WILLIAM T. ARCHEY, U.S. Chamber of Commerce; ELIZABETH HOLTZMAN, New York City Comptroller; CORRESPONDENTS: ROGER MUDD; JUDITH ASLET. Byline: In New York: ROBERT MacNeil; In Washington: JAMES LEHRER