When Melanie Mayron read an early script of the iconic yuppie angst-fest "thirtysomething" in 1987, she rushed to the telephone. The series' creators had portrayed her character, Melissa, as Jewish, fat and troubled. But the famously redheaded actress didn't want any of that. She'd already been a recurring character on another show about a food-obsessed Jewish chick, the 1970s sitcom, "Rhoda." And she was tired of the cliché.