I have seasrched and not found a trace to where John Yock came fom. I looked in passenger lists, but only found a Yost from Germany and it was a female. Could the name be Jock/Joak? My husband says that he was told years ago that the two sons where coming from England and that one went to China and the name changed to something like Joak. Could this be the connection? Also heard the rumour fo the German origin.