A few months back I used ancestry.com to accuse my 6th great-grandfather of incest. I based that on the doubling-down of DNA and some iffy generational numbers. “How can my 5th great-grandmother bear my 5th-great grandfather? Oooooohhh.”
This week I watched a NOVA episode on DNA that explained that it’s a range of DNA matches that determines a generation, and each range can overlap with the next range. So five generations back might be 32-43 matches, and six generations back might be 41-52 matches, and 42 matches might fall in either generation. Plus, the DNA analysis only goes back five generations, so that woman was outside of the DNA analysis anyway.
The NOVA episode also mentioned that when Ancestry.com checked my BRCA breast cancer genes, they only checked the three most common BRCA gene anomalies out of thousands.
Still, it was an interesting episode of NOVA,. I am ashamed to say I don’t always find NOVA fascinating anymore. Back in the 70s I loved it. The best episode was about Washoe the signing chimp. When I see the chimps at the zoo I always sign “BABY IN MY DRINK” in solidarity.
A visit to Wikipedia reveals that what I actually loved was a BBC show called Horizons, repackaged and re-dubbed for an American audience.
I have to admit that I conflate episodes of NOVA, Frontline, and American Experience. I have to take a moment to analyze the narrator voice I remember. Sonorous male voice? Frontline. Confidential soft female voice? American Experience. And, based on the most recent episode, NOVA is narrated by a chipper young woman. Encouraging for the girls today who need to get into the STEM field, but it doesn’t match with my ‘70s NOVA memories.