I have just made contact with a group of descendants of a line of CLEM/KLEMM and ancestors who share other various spellings of this surname. It appears that we all descend from Johann Davidt KLEMM (b. 1717) & Ann Maria (GOMAR). These are my 6th great-grandparents.
This cluster of descendants is being reassembled through autosomal DNA matching. Autosomal DNA matching is a very fickle process for cousins this far in the past. I only have a significant match with one of them. However, others show matches with each other and with my match. Autosomal DNA is almost an exact science back to second cousins. Only 90% of third cousins who are actually related will show up as matches. That number falls to about 50% for fourth cousins and about 10% of fifth cousins. Sixth and more distant cousins (the range of the KLEMM cluster) only show up as matches less than five percent of the time. This is because autosomal DNA is remixed with each inter-generational transfer. As this happens some of the adjacent portions of DNA are broken into smaller and smaller segments. After a few generations it is difficult to associate a particular segment of DNA with another descendant of that particular ancestor.
Johann Davidt KLEMM was born in Ittlingen and Anna Maria GOMAR was born in nearby Adelshofen. Both of these villages are in the Baden-Württemberg area of southern Germany. They appear to have been married there in 1741 before they migrated to North America. Their last child to be born in Ittlingen was born on March 21, 1746/7. One of their children was born in Pennsylvania on September 4, 1748. Their last child was born in Frederick County, VA in 1757. Johann Davidt died on March 10, 1787 at Powell's Fort Valley -- part of the Shenandoah Valley of Virginia.
It was in this area that Samuel GROVE, Sr. was born in 1785 and where he married Mary MOYER in 1807 before they moved on to Licking County, OH between the birth of their first child John in 1810 and the birth of their second, Anna, in 1812. They are my third great-grandparents. I can trace my GROVE/GROFF line back to Switzerland just before 1600. Our GROFF/GROVE ancestors were in Switzerland at the beginning of the 17th century and probably moved to Steinsfurt, Baden about 1675.
My KLEMM ancestors lived in Ittlingen and my 7th great grandmother Anna Maria GOMER was born in nearby Adelshofen--about an hours walk to the southwest. My GROVE/GROFF ancestors lived about an hour and twenty minute walk to the north in Steinsfurt around 1700.
Ittlingen was along a typical migration path for Mennonite/Ana-Baptist dissidents. By 1655 the first Swiss refugees settled in Ittlingen. We have yet to trace the KLEMM line back to Switzerland but it is certainly possible that was their location around 1600.
The Ana-Baptist/Mennonite dissident community was very tight knit community. I have discussed a more exact mitochondrial DNA match within this sect in a blog post a couple of months ago.