Endogamy is sort of like a scare word for genetic genealogy. It raises a specter of something terrible that will cloud your Ancestry or your DNA. We often see Cluster diagrams with few, big blobs of color that are not very helpful. Oh, woe is me, I have endogamy…
I say: just the facts, Ma’am… [which Joe Friday never really said]
Endogamy (and/or Pedigree Collapse) affects each person differently, but in a very specific way, in each case. Our DNA is fixed at conception – each of us has a very precise crossover points in our DNA, separating contributions from various Ancestors. We have a very specific set of DNA segments from our Ancestors. Any endogamy has already had its effect on our DNA, if any. Let’s just find out – let’s find out the facts!
1. Upload to GEDmatch.
2. Click on the free program: Are your parents related?
3. Read the intro paragraph
4. Enter you Kit#
6. View the results – green or red (match or no match)
Did GEDmatch find any substantial (over 7cM) green segments, in your DNA?
NO? Then, even if you had some endogamy or pedigree collapse in you Ancestry, you did not get any identical DNA segments from your parents. This means there is no effect when comparing with your Matches – every shared DNA segment with a Match will be from your father’s DNA or your mother’s DNA – no confusion!
YES? Then you do have some effect of endogamy or pedigree collapse in your DNA. BUT, it is confined specifically to the green segments. Write those segments down! Remember those segments! Put those segments into your master segment spreadsheet (two copies: one for each chromosome)! In DNA Painter: add those segments (one on each side) to highlight these areas.
All the rest of your DNA is free from the effects of endogamy or pedigree collapse. All other shared DNA segments with a Match will be from your father’s DNA or your mother’s DNA – no confusion!
Get the facts for your DNA! Free up as much of your DNA as you can.
IMPORTANT EPILOGUE – This blog post addressed the genetic, or DNA, part of endogamy. TGs are more definitive than Clusters, for example. But, it did not necessarily lighten the load on the genealogy side of our hobby. The issues of which Ancestor to link to which DNA segment (TG) remain.
[16F] Segment-ology: Endogamy – Get the Facts! by Jim Bartlett 20220425 EPILOGUE added 20220426