Tuesday, 7 May 2013

A Systematic Approach to Analysing your Autosomal DNA Matches - Introduction

Over the next few blogs, I will describe my first attempt at a systematic approach to analyzing your autosomal or X-DNA matches on FTDNA’s Family Finder, 23andMe’s Relative Finder or Gedmatch. Hopefully in time these techniques can be applied to AncestryDNA matches too. 

I developed this approach primarily to assist me and my own matches in working out our common connection, and while the focus is primarily on Irish ancestry, anyone can apply these techniques to their own particular situation. 

This does not represent “the right way” to approach DNA matches - it is only one way. There are probably many others. And in fact, in the spirit of community and sharing good practice, if you spot any mistakes or would like to suggest a better way of doing something, please do leave a comment and I will amend the blog accordingly. Many heads are better than one and frequently make light work. In fact, this is a work in progress and so the intention is to update and refine it regularly.

So, you’ve had your DNA tested, the results come back with more than 200 matches, and you wonder where do I go from here? The idea of contacting all these people and organizing the results is a daunting if not overwhelming task and it’s easy to get so far and then give up. This systematic approach may help make the task a bit more manageable, by taking one step at a time. 

Go through the process step by step. If a particular step doesn’t apply to you, just skip it and go on to the next one. Come back here to the introduction when you’ve finished. 

It’s best to start with one of your closest matches. The closer the match, the greater the chance of finding the common ancestor. To narrow it down even further, it would be best to choose a close match that also matches you strongly on the X-chromosome (this is discussed in Step 3).

Click on the step you want to go to: 

Step 1 – Where does the Common Ancestor sit on your tree (and your match's tree)? 
Step 2 – Is the Common Ancestor obvious?
Step 3 – Generate a Shortlist of possible candidates for the Common Ancestor (by identifying and/or eliminating ancestral lines that are “unlikely” or “highly unlikely” to contain the Common Ancestor)

Step 4 – Repeat Steps 1-3 with all your “Common Matches”
Step 5 – Compare Shortlists
Step 6 – Generate a Family Tree from your “Common Matches” based on the predicted relationships
Step 7 – Further Documentary Research to identify the “Common Matches” (or at least the surname of the Common Ancestor)

If there is anything that is unclear or any aspect that you would like me expand on, please leave a comment below the appropriate step and I will do my best to address it.

You may also like to check out Roberta Estes blog which explains Autosomal Results - The Basics.

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