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

Chava is Tevye's third daughter. She falls in love with Chvedka the scribe, who she compares with the Russian novelist Gorky. Chava decides to marry the non-Jew Chvedka, even though this means coming under the protection of the town Christian priest. Tevye decides there is nothing he can do to stop this, and declares that Chava is dead and mourns for her.