Archive by Author | Kitty

Thank You from Rockstar number 7

Thank you all for voting me into the top ten again this year. Special thanks to John D Reid for doing these yearly top ten lists in various genealogy categories. It means a lot to me to have this kind of recognition for all the work I put into helping others with this wonderful hobby.

This year’s genetic genealogy top ten really does include folk who are primarily DNA oriented as opposed to previous years where a number of well known genealogists who are not known for DNA were on the list. Click here for what I wrote last year.

DNA has fascinated me since high school biology when I learned about Mendel and dominant versus recessive genes.
Continue reading →

MyHeritage DNA matching is here!

Sep6

The first release of a new feature, is always exciting but just as often it is also disappointing because it is missing functionality that you expected. I am told that the things I missed the most – search by surname, sorting options – will be implemented, but I did not get a commitment on getting a place to put notes.

If you previously uploaded your DNA kit, you can now see your DNA matches at myHeritage by clicking on the tab Discoveries and then on DNA Matches in the drop down (the red arrow in the image is mine as usual). When you have more than one kit there is a drop down to select which kit’s matches to view (a tiny down arrow to the right of your name after the words DNA matches for).

Your matches appear in an attractive list, each in its own box with some information. My known second cousin John is shown below. Scrolling to the bottom gets more matches. There is no paging yet.

If you have not yet uploaded your DNA then go to your tree and find the person whose DNA test you wish to upload. Click on the words Upload DNA data and then follow the instructions.

MyHeritage announced the release of this DNA matching feature in today’s blog post at
http://blog.myheritage.com/2016/09/dna-matching-now-live/
where they explain that they are using imputation (DNA.land uses a similar technique) to match people from all different companies and chip versions and that they are confident in their accuracy.

So how do these matches look? My close family looks fine. Dad, myself, my brother, and a second cousin who uploaded his data. Cousin John is listed as a second cousin to my brother and myself but he shares 294.9 cM with a largest segment of 81.5 over at GEDmatch. Somewhat different from the image above where his largest segment is close enough at 81.1 but the total is lower at 211. Perhaps that is because I used my brother’s ancestry kit. Checking my own match with him, there is also less shared DNA at MyHeritage (188cM) than at 23andme (283 cM). Even if we remove the 14.4 cM on the X from that total.

But the less close matches are not looking quite so good.

Continue reading →

A Few Reminders and Please Vote

Sep3

This is the last call for you to contribute your X chromosome statistics to my survey. Click here for my post explaining the project.

This is the fifth year of the survey of best genealogists in a number of categories conducted by Canadian genealogist John D Reid at his blog Canada’s Anglo-Celtic Connections. Please vote for your favorites.

This is the second DNA only conference by I4GG.org so don’t miss it. It will be in my hometown, San Diego, the weekend of October 22-23. The weather will be lovely, as always, and I will be doing a session on the tools at GEDmatch.

And my final reminder, please contribute your DNA statistics to my study on the differences between half siblings matches versus aunt/uncle/niece/nephew matches versus grandparent /grandchild matches. This is particularly important for helping adoptees. The hope is that when they get one of these matches, maybe it would be possible to tell which relationship it is without testing more family members. Click here for my post on that.

Michelle’s AncestryDNA tips

Aug23

No matter how expert you think you are, there is always something to be learned from others.

When I saw that Michelle Trostler of DNA Detectives on Facebook and Identify Family was giving a talk on getting started with AncestryDNA for my local DNA special interest group, the North San Diego County Genealogical Society, I knew I should go, and I am glad that I did.

Personally, I use the Ancestry.com DNA testing service the least of the big three because all my ancestors are relatively recent arrivals (late 1800s and 1930s) so I do not have as many DNA matches there as elsewhere. Thus I know far less about using that site than the others.

Michelle is a knowledgeable and confident speaker. You can hear her at the upcoming i4GG seminar in San Diego as well.

Here are some of the tips from her talk that I found particularly useful.
Continue reading →

How to tell the relationship from the shared DNA

Aug14

Many people have the illusion that if their testing company says a person is a 3rd to 5th cousin they really will be. That is not the case.

The testing companies are just making the best guess they can from the data they have. They do not seem to take segment sizes into account, rather they primarily use total shared DNA measured in centimorgans (cMs) for their relatedness estimates, usually the sum of all matching segments of 5 cM or larger. Close relatives will always share larger chunks with each other and so size does matter here.

Recently I have received numerous questions from people trying to figure out if a new match is a half sibling or a niece or a grandchild. These are hard to tell apart without testing more relatives as they all share about 25% of their DNA with each other. So I decided to collect some detailed statistics on those specific relationships with a google form (click here) that includes total segments and segment sizes for a future blog post [UPDATE as of sept 2017: First round results are written up at https://blog.kittycooper.com/2017/09/the-25-relationship-a-first-look-at-the-data/ ]

The companies predict reasonably well for close family but it is just not possible to be accurate beyond that due to the randomness of DNA inheritance.

For example, here is a picture from the new 23andme of some of the DNA I share with Dick, a 2nd cousin on Dad’s paternal side so blue, and John, a 2nd cousin on Dad’s maternal side so red.

I share a third again as much DNA with John as I do with Dick, even excluding the 14 cM on the X. The expected amount for a 2nd cousin is 3.125% which is 212.50 cM, right in the middle between these two.
Checking my brother, I see the same effect – he has 282 cM with John versus 185 with Dick. Not surprisingly, when I look at Dad I find that he shares almost twice as much with John as with Dick. Clearly he just inherited more of the same DNA as John’s mother from their common grandparents. Conversely, he inherited less DNA shared with Dick’s mother from his other grandparents.

On the left is a comparison of my first cousin Henry with both Dick and John. The amount he shares with each 2nd cousin is practically identical, as long as you subtract the 40 cM that he shares with John on the X from the total shown by 23andme. Amazing how variable DNA inheritance can be among 2nd cousins.

Click here for the ISOGG wiki article on Autosomal DNA statistics which usually includes the current chart from Blaine Bettinger’s shared centimorgan DNA project.