G2G: Exact match for Big-Y but no paper trail matches back 5 generations

Question

I have an exact Big Y match with 4 of 515 STR differences with someone with the same last name. We both have paper trails back to the early 1800s with no overlap or holes that might explain such a close match. The earliest ancestor of my match was an orphan named David (single child) who was born in PA in 1801 and raised by his maternal grandparents. My earliest ancestor was named George, born in VA in 1815 (he had two older siblings born in 1809 and 1810). This leaves me with a few possibilities:

1) David's father was not dead, but "missing" and he went on to father my branch.

2) David's father and George's father were brothers.

Are there other possibilities that I am overlooking? Is there a clue hidden in my results or an additional test we can take to determine how far back our match is? Thanks in advance for any help you can provide!

Answer 1

Matching on 511 out of 515 Y-STR markers is quite possible for a shared patrilineal ancestor before 1800.

Answer 2

How many private SNP variants do each of you have? For BigY700 tests, average the number of private SNP variants and multiply by 83 years to get a rough estimate of when the common ancestor lived. (The calculation for the older BigY test (which tested fewer SNPs) is different, and I don't know offhand what it is.)

Comments

I'm not at all knowledgeable when it comes to DNA, so
I appreciate your patience with me. I checked my results and I don't have any private SNP variants. I don't know if my match does. I did notice that we have 15 non-matching and 535234 shared variants. We are the only two in our haplogroup. Does that information help me narrow the timeframe back to our common ancestor?

---

Hi Jana, the new Discovery tool on FamilyTreeDNA will provide you with a time estimate for when you connect.