The whole argument whether all Jews are of semitic origin is foolish. Judaism permits converts, and these converts can come from any ethnic group, and a convert is for all intent and purposes (of course I assume an Orthodox conversion process) is as Jewish as a born Jew. Even our great leader Rabbi Kahane stated this numerous times in his talks, that a convert to Judaism is as Jewish as Rabbi Kahane...
Those who try to make it all a genetic thing are just racists, all who try to suggest that Jews have no link to the semitic (descendants of Shem, son of Noach) people are wrong. The diaspora sent Jews to the four corners of the world, and we mingled with our host countries marrying converts to Judaism. To argue about whether all Jews have semitic DNA is foolish...