Who is Chava from Tevye the Dairyman and the Railroad Stories and what is their importance?

Chava is Tevye and Golde's third daughter. She falls in love with a scribe named Chvedka, who she compares with the great Russian novelist, Gorky. Chvedka, however, is not Jewish, and her marriage places her under the protection of a Christian priest. Her father declares her dead and mourns her loss.