I took the Y-DNA test through FamilyTreeDNA.com. Since "Emlen" is such an uncommon surname, I wasn't expecting to see any matches at all. But I was pleasantly surprised to find that I match someone (with a genetic distance of 1, at 37 markers) with the last name of "Emblin", who can trace his ancestry back to about 1720 in Stoke Lane, Somerset. Stoke Lane is only about 5 miles from Shepton Mallet, where my emigrant ancestor George Emlen was born.
With a genetic distance of only 1, we shouldn't have to go back too many generations before George Emlen to find the common ancestor with the Stoke Lane Emblins. But the paper trail (i.e. birth, death, marriage, etc. records) that would show the connection either doesn't exist or hasn't been found yet.
DNA testing could help solve another mystery in the Emlen family tree: are the Emlens of Burlington County, New Jersey (whose descendants now live in Illinois) also descended from George Emlen, or are they actually descendants of William Emley (1648-1704), who was born in Blyth Parish, Nottingham, England and emigrated to America (New Jersey) in 1678? Contact me if you're an Illinois Emlen or a Burlington County Emley who has taken or is considering taking a Y-DNA test.