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Hello, my name is Judas Gutenberg and this is my blaag (pronounced as you would the vomit noise "hyroop-bleuach").


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Like my brownhouse:
   placing trace ancestors in time
Thursday, October 20 2022
Since the genomic database update at 23&Me that suggested that 0.2% of my genes are Gujarati Patidar, I've been thinking about who that ancestor was and how he or she came to find him or herself injecting genes into the gene pool of northwestern Europe. I figured I could get a rough estimate of when that Gujarati ancestor (assuming there was only one, as is likely) lived by figuring out what power of two gives me 0.2%. The absolute value of that number is how many generations ago that ancestor lived. Doing this calculation in my head, I came up with the number eight, which I then multiplied by 25 (widely accepted as good approximation as the average age difference between generations) to get 200, which means this ancestor lived about 200 years ago. For some reason I was sloppy and subtracted this from 2000 to get 1800 as the year that ancestor was born. But this process was filled with numerous errors, including the fact that I was born in 1968, not 2000.
So this evening after work, I thought I'd put a little more effort into this calculation by making a table of the percentages of genes I got from different ancestors (organized by closeness of familial relation) with information such as when these ancestors were born. I then started with the oldest generation for which I have birthyears of all my ancestors (great-grandparents, in my case) and calculated approximate generation spans from there, working all the way back to the percentage of relation that the Gujarati had contributed to my genes. Initially, since generations in my ancestors had tended to be longer than average, I used 30 years for the first unknown step backwards into the past, though after that I used 25 years (since, as with most exceptional traits among replicating organisms, they usually quickly revert to the mean). Doing this, I came up with a birth year of about 1700 for the Gujarati, who would be my great-great-great-great-great-great-great grandparent. Using this same methodology, I also placed the birth of my Coptic Egyptian ancestor at about 1725, the birth of an Italian ancestor at about 1775, and the birth of an ancestor in Eastern Europe at about 1800. Since I have actual birthdates for great grandparents as early as 1839, that gets us pretty close to known individuals. My thinking for now is that the Gujarati and Coptic Egyptian genes came in through my great grandmother Carolne Abbott, since she is the biggest mystery in my family tree, is always described by members of my mother's family as being "from Canada," and the other 23&Me customers with near-Eastern genes seem to be from somewhere near her part of the family tree.

Here's the chart I came up with:

genetic contribution percentage who year born possible trace ancestor relation methodology
100 Gus Mueller 1968   self  
50 Elizabeth DeMar 1937   mother 
50 Robert Mueller 1923   father 
25 Margaret Ilsley 1896   maternal grandmother 
25 Clarence DeMar 1888   maternal grandfather 
25 Katherine Deschler 1890   paternal grandmother 
25 John Mueller 1881   paternal grandfather 
12.5 Sarah Barlett Lobdell 1872   maternal great-grandmother 
12.5 Charles Danforth Ilsley 1865   maternal great-grandfather 
12.5 Caroline Abbott 1869   maternal great-grandmother 
12.5 George Washington DeMar 1856   maternal great-grandfather 
12.5 Lena Putz 1854   paternal great-grandmother 
12.5 William Deschler 1854   paternal great-grandfather 
12.5 Anna Maria Schneider 1848   paternal great-grandmother 
12.5 Johannes Mueller 1839   paternal great-grandfather 
12.5 1857   average birthyear of great-grandparents 
6.25 ~1827   great-great grandparent subtract 30 years because generations tend to be longer in my family
3.125 ~1803 Eastern European great-great-great grandparent subtract 25 years, reversion to mean of generation length
1.5625 ~1777 Italian great-great-great-great grandparentsubtract 25 years
0.78125 ~1753   great-great-great-great-great grandparentsubtract 25 years
0.390625 ~1727 Coptic Egyptian great-great-great-great-great-great grandparentsubtract 25 years
0.1953125 ~1703 Gujarati great-great-great-great-great-great-great grandparentsubtract 25 years

This evening Gretchen made a big pot of potato-kale soup, to which I added bits of poblano pepper and oyster crackers, and it made for a great chilly-weather dinner. We watched another episode of Bad Vegan with increasingly alarm as obvious psycho conman Anthony Strangi led Sarma Melngailis down his rabbit hole of madness and manipulation. Watching all the wire transfers flip by, the ones Anthony managed to get Sarma to send him, reminded me of all those IOUs my mother wrote to Sara Kesterson, though that scam was an order of magnitude smaller.

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