Maybe you tested your DNA to prove or disprove a genealogical theory. Or maybe you tested to check on your health risks or carrier status. But now you see all these possible 3rd to 5th cousins in your family finder or relative finder lists and you wonder if you are related and if you can find that relationship. Perhaps you contacted a few and had almost no responses.
Yes you are probably related, but without both of you having a good paper trail you would be most lucky to actually find that relationship. It is likely to be further back than suggested if your ancestors were at all endogamous. Just living in the same location for a few hundred years can lead to much inadvertent intermarrying and more common DNA than degree of relationship would expect. So autosomal DNA testing is no genealogical shortcut. Some of the people you contacted already know this, so if they saw no common surnames or places on your profile they may have lost interest.
So be prepared before contacting those likely 3rd to 5th cousins.
- Have an easily readable pedigree chart in both PDF and online format (GEDmatch can do the latter, more on GEDmatch later)
- Another good tool is a list of about 12 generations of ancestors by place name. Much easier for a possible relative to scan.
- Do some reading on the basics. A nice short article on autosomal DNA is this one on about.com and it has some more links.
- Try to talk some close relatives into testing so you have more data to work with
- Last but not least, make a decision on how much time you want to devote to this project … warning it can be addictive
If you want to do the minimum, then scan the localities and surnames of these possible cousins and contact the ones with surnames or place names in common with you. Indicate in your message that this is the reason for contact. Include the URL for your pedigree or family site and offer to send the PDF files. Include your email address if you are using the 23andme messaging system. The more directed the contact, the more likely you will hear back. I recently went through and cancelled some of my early invitations and send new improved ones on the lines above and got four new shares.
You might enjoy reading this relative finding success story from CeCe Moore on her blog.
If genetic genealogy and your DNA relatedness really interest you then you want to start a master spreadsheet of the DNA segments that you match your possible relatives with. If one or both of your parents are tested, then create one for each parent as well. I did a post about creating a DNA match spreadsheet a while back. This post will discuss more of the whys and wherefores. As a reminder, on 23andme you can find overlapping segments by selecting My Results in the top menu then Ancestry Tools then Family Inheritence: Advanced. At Family Tree DNA you select up to five people to show in the chromosome brower and then go to that browser.
Part of the objective is to find overlapping segments and thus clues to where the relationship might be. Many people enjoy building a picture of which distant ancestors their DNA came from when they do find the relationships (or just get more relatives to test).
So the first question is how large a segment is worthy of being included on this sheet.
Many genetic genealogists suggest that a one segment match of less than 10 cMs will not have a common ancestor in the last 200 years and thus hard to find the relationship. Plus matches smaller than 7cM may not even be IBD (identical by descent) since the smaller the match the more likely that it is not real, but rather IBS (identical by state). Remember you have two copies of each chromosome and the testing cannot say which side each allele came from.For example, if you are AA GG AA CC you will match me when I am AG AG AG CT but there is no guarantee that my A G A C came from a single side (paternal or maternal) so we need a much longer match to have some confidence that we are related.
There is a good explanation of this IBS vs IBD concept here: http://dna-footprints.com/203/the-abcs-of-dna-ibd-vs-ibs/
There are a number of charts on DNA relatedness, the ISOGG website has several, I like the one on their IBD wiki page because I find the number of segments most useful. The family tree DNA FAQ has some very useful snippets also.
Personally on my spreadsheet I show all matches of about 6cM or more for any non Ashkenazi relative with three or more matching segments. I show single segment matches of 7cM or more. But those are just my choices, not necessarily real relatives. Since I have tested my father and brother, I can assume a smaller match is IBD when it is passed on (often a bit smaller) from Dad to one of us since our mother is from a completely different population group. My post on common relatives can be far back shows some of those smaller matches where the MRCA (most recent common ancestor) has been found, usually well before 1800 some before 1700.
The second question is where to find the matching segment data.
- On family tree DNA you can go to family finder and matches, click Chromosome Browser and painstakingly go through all your matches. Or you can assign the more interesting ones as possible relatives and then they are easier to find in that function. But there is a better way, use the tools at http://www.dnagedcom.com to download all your chromosome matches, then sort the file first by match size and discard all matches below your chosen threshold. Then create two more files from that file, one sorted by name and the other sorted by chromosome and start point. The second file is the basis for your master sheet
- On 23andme, you can get a master list of overlapping segments from ancestry labs > ancestry finder. Wait for the page to load and then scroll down to the big button that says: Download yourname‘s Ancestry Finder Matches. However the problem is that many of these are listed as anonymous even when you are already sharing with them. So you need to share genomes with the anonymous ones to put a name to a segment. You send those invitations out via relative finder. The tools at at http://www.dnagedcom.com will download all the matching segments from your shares. Once you have a combined master list make two more files, one sorted by name and the other sorted by chromosome and start point. The second file is the basis for your master sheet
When you find an overlapping segment with more than one possible relative be sure to check if they match each other too!
I have a number of cases where the same rounded off segment at 23andme which matches me is not a match between two relatives because they are related on different sides, one paternal and one maternal. To check at 23andme use the chromosome browser function and compare your two matches. At family finder, use the in common with function to see if one match is in common with the other one. Then they match each other. Of course that is no guarantee that they don’t match somewhere else instead so ask them if they match each other there or (best) compare them at GEDmatch. Alternately if you have other family members tested at family tree DNA you may be able to look at their match with these two (see a later post I did on that technique).
If you have uploaded your data to GEDmatch you can use the GEDmatch site to look at specific matching segments of interest to see if there are other possible matches. That is the “Show results that match on a given chromosome segment” function. Then you can check if your possibles match each other as well by comparing those two id numbers using the “Compare your Autosomal FTDNA or 23andMe result with one other result in our database” function. The start and ending segments are shown as well as the cMs and SNPs.
Since my mother and father are from such different population groups, I now only do my mother’s side in my own spreadsheet and keep a separate spreadsheet for Dad. My current focus is Dad’s Norwegian ancestry (with a sprinkling of Finnish and British see his chromosome ancestry picture in my post about ancestry tools at 23andme) since records in Norway are great and very much online so we have a long paper trail. Plus we have solved one brick wall already with DNA!
If you want to go even deeper with your spreadsheet approach, I recommend joining the DNA_NEWBIE group via the ISOGG website and looking through their files on methodology as well as joining the genealogy-DNA group at rootsweb and reading all back posts by Tim Janzen.
More another day.
I have updated this post a little and added it to the DNA testing menu. Other posts to read as follow up are Jim Bartlett’s post on using spreadsheets and my page on the overlapping segment mapper, if you want to make a pretty picture from the CSV of your overlaps from your 40 closest DNA relatives.