Archive by Author | Kitty

Ashkenazi DNA: we are all descended from 350 people in medieval times

Most of my DNA explorations have centered around my Dad’s Norwegian DNA because so many Norwegians have tested and the populations of those ancestors are only mildly endogamous; so it is easy to find new cousins and fun to work with those results.

My grandfather and me, summer 1955

My mother’s father was a German Jew. The number of DNA matches this gives me, my brother, and my two maternal aunts is astronomical. Frequently I will match someone from Eastern Europe for five or six large segments who cannot share an ancestor with us for the last 200-300 years and is even listed as a “distant cousin.” If they were Norwegian, that amount of shared DNA would make them my 2nd cousin.

This has been so frustrating that I just about stopped working on my Jewish DNA. A fellow Jewish researcher told me to ignore matches who did not have at least one 23cM shared segment!

Today there were dozens of news articles about the European Jewish founder effect suggesting that all Ashkenazim are descended from about 350 people who lived in about 1300 A.D. or so. This, combined with a fair amount of endogamy, would explain the large amount of shared DNA among European Jews.
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More genealogy blogs to follow

Sep7

I felt like reading more genealogy blogs about Norwegian genealogy research and also wanted to check if there were any on DNA that I was missing, so I headed over to Geneabloggers for a look. I used the search function on their list of over 3000 genealogy blogs and added a few more to my list.

I miss the old igoogle page where I organized the RSS feeds from all of the blogs I read. I now use protopage to organize the feeds from the blogs that interest me.

Of course I have subscribed to my favorite blogs via email updates. In case you missed it, there is an email sign up at the very bottom of the right column here on my blog. Unlike some, instead of sending the whole post, it sends the first paragraph from each of my last five posts so you can click through to what interests you.

Segment Mapper Tool Improvements: another Wold DNA map

Sep2

The segment mapper can now make a picture from an unlimited number of people, as long as you specify a color for those above 40. Also colors can be specified for every person. Additionally if you want to use a smaller number of tracks than four, it now will use the extra spacing correctly.

These enhancements all came about because I did not like the way my picture of the DNA inherited from my Wold ancestors in my previous post came out. So here it is again. I added a few more people, made it three tracks, and started playing with the colors. More improvements on the way, like fixing the long key to go side to side.

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Mapping an Ancestral Couple: a Backwards Use of my Segment Mapper

Aug29

Sometimes I wonder if the interest in genetic genealogy runs in our DNA. I have found many more new cousins with autosomal testing that are descended from my WOLD line than in any other family. Yes they all had lots of children until recently, but so did the Munsons and the Skjolds.

So I decided to make a picture of the HIR (half identical region) DNA segments that I know come from my great-great-grandparents Jørgen and Anna Wold of Drammen, Norway. To do this I made a CSV file with a list of all the segments that are just from those ancestors. I put the first names of the group of matches in the column that would be the MRCA in the usual style segment map. I have to give credit to my distant DNA cousin (on the AJ side) Israel Pickholtz (he blogs too) for this wonderful idea of making a reverse segment map. Below is my picture of Wold DNA created with my DNA segment mapper tool. Click the image to go to the actual html page which will show the centimorgan values and names when you put your mouse on a colored block.

The use of two lines is arbitrary; I could have used three or four. The DNA segments shown are not separated into lines for Anna and those for Jorgen. Where that was possible, I had intended to do it with colors, but did not get to it, next version. Knut, OK, Nancy and Aaron are on Anna’s side while Susannah, her mother, and Lester are on Jorgen’s side only.
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The DNA of eye color: it’s complicated

Aug25

In high school I learned that blue eyes were a simple recessive gene so two brown-eyed parents could have a blue-eyed child but not vice versa. Recently I discovered that this was wrong. Many genes are involved in eye color and with the subtle variations in eye coloring.

GEDmatch.com eye color prediction for me

So I ran the fun eye color calculator at GEDmatch.com and discovered that it shows many of the SNPs involved in my eye color with the details of what they each do.

I had not realized that blue eyes are caused by the lack of (brown) melanin, so really are no color. Blue happens the same way the color of the sky does: light is bounced around in a way that appears blue according to the wikipedia article on eye color. Maybe that is why my eyes appear greenish when I wear certain green shirts and turquoise when I wear those color shirts.

If the two blue-eyed parents have their lack of eye color melanin caused by different genes then they could have a brown-eyed child. I happen to know a brown-eyed child of green and blue-eyed parents (and she looks just like her Dad so not what you are thinking). This case got me curious about how that could happen. So I googled around and found this wonderful article that explains it: http://genetics.thetech.org/how-blue-eyed-parents-can-have-brown-eyed-children

Here is my attempt to simplify the ghist of that article: