Archive | 2014

A deep DNA triangulation success story

Jan23

So many of these one segment DNA matches that I find with other testers are too far back to find the common ancestors. However those of us with Norwegian ancestry often have very deep trees thanks to the good records and the many farm books for each locality. So when you find a fellow genealogist with Norwegian roots who matches your DNA you get quite hopeful, and sure enough …

I had four matches, the colored lines in the picture below, for my Norwegian descended Dad on chromosome 16. However they span the centromere which is from 35335801 to 38335801, so initially these segments did not seem that promising.

Chromosome 16 from my one segment mapper tool

Four people overlapping on Chromosome 16
from my one segment mapper tool

Luckily the most recent match had an extensive tree of which only a small piece was Norwegian. So perhaps it would be easier to find our common ancestor with less tree to look through. Note that using a tool to compare Norwegian GEDcoms does not usually work so well because of differences in naming conventions (patronymic, farm name, Norwegian characters, etc)

Here are the details of these segment overlaps from my master spreadsheet for Dad:

Edith 16 31000000 52000000 9.20 1301
Nancy 16 31000000 54000000 9.70 1359
Loretta 16 31000000 52000000 9.90 1423
Aaron 16 33000000 53000000 8.2 1241

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Organizing your Autosomal DNA Information with a Spreadsheet

Jan17

By Jim Bartlett

Impressed by Jim Bartlett’s prose on various message boards and mailing lists, I asked him to do a guest blog post on using spreadsheets with autosomal DNA results, here it is – Kitty

jvb-in-coat-and-tie-cropUsing autosomal DNA testing can be a challenge – but it doesn’t have to be. It can be intimidating – but by taking it a step at a time, you can break it down into bite-sized pieces that are much easier. When you decide to use autosomal DNA (atDNA), and to get the most out of it, I recommend three broad areas of focus right from the start:

  1. Learn all you can about DNA testing for genealogy and particularly about autosomal DNA (atDNA). The ISOGG wiki is a good place to find good articles, tools, blogs (to keep you up to date), etc. Join email lists and read and ask questions. This is definitely a “continuing education” hobby. We are on a frontier with genetic genealogy – and we are pushing the boundaries every day!
  2. Create as robust a Tree as you can – stretch as much as you can to 12 generations, or more. This is the net you need to catch cousins and find your Common Ancestors. This is very important – if you don’t have the ancestors in your Tree, you cannot expect to find a Common Ancestor with a Match.
  3. Set up a process for your autosomal DNA project. To determine Common Ancestors you have to share ancestry info with your DNA Matches – you’ll be sending (and receiving) a lot of emails and messages. You’ll want to keep track of what you do; to find info on your Matches; to remember the Common Ancestors you determine; new names, new emails, new links to Trees, etc., etc. You may want to use a spiral notebook as a Diary or Journal of your notes. Some people keep a notecard for each Match, or a folder. I now have over 3,000 matches at FTDNA and 23andMe, so I need something that can handle that many (and more) Matches. Many of us use a spreadsheet – read more to see how to set up one.

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What does shared X DNA really mean?

Jan6

Since familytreeDNA added X chromosome matching to their family finder, all my favorite bloggers have been writing about how to use it. There is a list of their terrific articles at the end of this post.

Of course those of us who have many family members tested at 23andme have been working with the X chromosome for a while and have some thoughts on how useful it might or might not be.

  1.  Smaller matches on the X will usually be too far back to find the relationship because the X chromosome does not get recombined when a father passes his only X chromosome on to make a daughter. Thus segments can stay together longer in time.
  2. A match on the X can eliminate many ancestors from an autosomal match BUT a small match on the X can be from a different line so this is not guaranteed.
  3. There seems to be less recombination on the X. I have heard of cases where a child got an unrecombined X from their mother. In my own family, the number of recombined segments is quite small. So it seems to me that on the female to female line the X behaves like a sluggish autosome and is not quite as actively recombined as the other chromosomes. [UPDATE 11-May-2018: the X has been shown to have a normal amount of recombination for any chromosome by a citizen science study done by Blaine Bettinger, click here for blog post by Leanne Cooper summarizing this.]

Less recombination examples

Because our maternal line (1/2 Ashkenazi, 1/2 Bavarian Catholic) is from two different population groups, my brother and I can learn which maternal grandparent we got our X DNA from just by looking at the ancestry composition for that chromosome at 23andme:

XchromCompare Continue reading →

My contest for a free pass to RootsTech 2014

Jan3

One lucky reader will get a free pass to Rootstech 2014 this coming February (an educational event for the howtos of using technology in family history research), since I will be an official rootstech blogger. So my idea was to award it to whomever comes up with the best question for me to ask Spencer Wells at the conference. I am expecting to have a private interview with him, video recorded and posted here. So send me your questions via my contact page by January 30th.

It was Well’s book, Deep Ancestry: Inside The Genographic Project, that sparked my interest in population genetics and genetic genealogy. After I read it, I did the original NatGEO DNA test. Then I transferred the results to FamilyTreeDNA.com but my mitrochondrial DNA was too deep in the past to satisfy my genealogy cravings. Soon thereafter I heard about 23andme and tested there. Twisted the arms of many family members and relatives to get tested, including my father, whom I had tested by both of those sites. In the process I read lots of books and blogs. The marriage of genes and genealogy known as genetic genealogy had me firmly hooked.

Read on for more about all the things I have enjoyed reading to expand my understanding, n.b. favorite blogs are in the column on the right towards the bottom. Continue reading →