The Yohe Surname Y-DNA project is up and running at http://www.worldfamilies.net/surnames/yohe
This project seeks to sort out the various Yohe lines in the United States and help determine how we're related, if we are.
Y-DNA is passed directly from father to son, possibly with minor mutations between generations. It is a reasonably reliable way of determining whether two males who share a surname may have a common male ancestor in recent generations (or whether that is unlikely).
If you are a Yohe-surname male descended directly (and biologically) from one of the Yohes who came from Germany to Pennsylvania in the 1700's (or even if you are descended from some other Yohe or do not know your ancestry) and are interested in participating, please visit the project site or contact me for further information.
Mike Yohe g3gs/o Michael Yohe (1746-1832)