Miriam Lois Frankel was born in Chicago on Sept. 21, 1919, the only child of Daniel Frankel, a salesman who later produced nightclub shows, and Miriam Elizabeth (Bly) Frankel, a seamstress who went on to a show-business wardrobe department career. At 19 she made her Broadway debut, in Sing Out the News (1938), a musical revue, with June Allyson, whose songs included Sing Ho for Private Enterprise. In 1941, two weeks after Pearl Harbor, she married Gene Nelson, a fellow dancer and actor. They moved to Los Angeles, and good luck followed. Having…