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What to do with your DNA test

Some of my cousins and friends have tested at 23andme or familytreeDNA, due to my urging, and now they are asking me what to do next. I dedicate this post to them.

Autosomal DNA testing will not not magically find your ancestors. You will need to work at it and may have very little success if not enough of your known and unknown relatives have tested. It will give you many clues and hints about where your ancestors were from. Be sure to use some of the admix tools at GEDmatch.com on your results if that interests you, see my post on GEDmatch.

I suggest that if you are not familiar with DNA or DNA testing that you read my DNA basics page and if you have tested at 23andme also read my post on 23andme basics.

Assuming that you all do not want to spend the kind of time on this that I do (an hour or two most days for the last year); here is how to get the most for the least time input.

First you need to understand that an autosomal DNA test is nowhere near as definitive as a Y chromosome test, it can show you that you are related because you share runs of identical SNPs (referred to as segment matches from here on) with someone but not exactly how or even how close. After the 2nd cousin level the amount you will share with a relative gets more and more random. I have a few 9th cousins I share a one segment match with who like me have extensive trees and that is the closest match we have found. ISOGG has published the expected ranges of cMs and number of segments on their wiki that relatives share at different levels of relationship.

So what was your objective taking the DNA test? If it was just to satisfy your curiosity then my post on 23andme basics should answer your questions. If finding new relatives is of interest then read on.

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Results for a second cousin on the Skjold line

The results for our second cousin John who shares Skjold and Wold ancestry are just in today at 23andme so of course the first thing I did was compare him to me, my brother, my dad, and a few other cousins. Interestingly John has inherited far more DNA in common with us than our Munson side 2nd cousin has.

Dad shares 608 cM over 25 segments with John and only 389 cM within 18 segments with Dick, our Munson 2nd cousin. My brother shares 281 cM over 13 segments with John as opposed to 155 cM over 7 segments with Dick while I share 282 cM in 15 segments with John as opposed to 175 cM within 10 segments with my Munson 2nd cousin Dick.

Here is a pretty picture I made with my chromosome segment mapper tool:

Our 2nd Cousin on the Skjold line from Segment Mapper

Overlapping DNA from our 2nd Cousin on the Skjold line compared to family with the Segment Mapper

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My Double 3rd cousin versus my brother and my Aunts as shown with my segment mapper

The results came in for my other maternal Aunt so now there are four of us to compare to my double third cousin and still no match on the X! In order to show the comparisons I used my new nifty chromosome segment mapping tool and also added in a bunch of known 5th and 7th cousins to the diagram.

Dbl3rdCOusin

Click on the diagram to go to the full size html page made from the segment mapper. Note that Shipley Munson is my brother.

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Areas of faster and slower mutations in our chromosomes

A team of Penn State researchers has made a map of human chromosomes that shows the areas where mutations are more and less frequent; in their words “mutationally hot and cold regions.” However I found their diagram extremely difficult to understand. It took me quite a while to figure out the areas that are hot and cold for the SNPs that genetic genealogists are interested in. So I redid their image, removing the color for microsatellite repeat alterations, and changed the colors a little to be more in tune with hot and cold for me.

Here is my version:

HotColrAreas
Hottest
  Hot
  neutral
  Cold
  Coldest

 

Gray presumably are the areas not done and white outlined with black shows the centromeres. The one place with the least mutation is the X chromosome.

 

No guarantees that my reinterpretation of the graph by Kateryna Makova and Francesca Chiaromonte is correct!


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First version of the DNA Segment Mapper is Released

So many people were trying to use my DNA chromosome mapper tool to look at a picture of their DNA relatives’ matching segments that I realized that another tool was needed to meet that demand. The first version of the new DNA segment mapping tool is ready. More information is at http://blog.kittycooper.com/tools/segment-mapper/

Sample Output from the DNA Segment Mapper

Sample Output from the DNA Segment Mapper

 

The DNA Segment mapper can show the matching DNA from up to 40 people in a chromosome style chart. Here is what my Dad’s top 40 matches look like (names are removed). The first two are first and third cousins once removed.

There is a page under tools above with more complete description and documentation.