A Triangulation Feature on the New 23andme

An exciting triangulation feature has just been released at 23andme. It is only for profiles that have transitioned to the new site and have selected open sharing (for now). The feature shows you the relatives you have in common with one other profile and whether or not they triangulate with the two of you.

To use this tool you go to Tools > DNA relatives > People and pick a DNA relative to look at. At the top of the comparison page there is a menu item “Relatives.” Click on it to skip down the page where you will see a display like this (names removed for privacy):

RICsmll

When there is a “Yes” in the right hand column, there is a DNA segment in common between the two people you are comparing and this third person thus you triangulate. A “No” means that although you each share DNA with this relative, there is no segment of DNA where all three of you match. Click on the Yes (or a No) to see the three of you compared in the chromosome browser.

Once in the chromosome browser, you can use the “Update View – Edit” to add more people to the comparison with the first person. This is the same chromosome browser that you get to from Tools > DNA relatives > DNA

Jason Lee has done a nice write up with more details on his DNA blog at Tumblr:
http://dnagenealogy.tumblr.com/post/144966221253/relatives-in-common-quick-reaction

Sadly you cannot use this tool with relatives still on the old site, since they have not yet been able to opt in to “Open Sharing” yet.

It’s almost time for Jamboree!

The Southern California Genealogical Society puts on a wonderful genealogy conference every year in Burbank in early June. There are only a few days left to register so, unless you have done so already, head over to http://genealogyjamboree.com/2016/about.html by May 22.

Thursday June 2 is DNA day and there are many terrific presenters and topics: Tim Janzten, Blaine Bettinger, Diahan Southard, Emily D. Aulicino, Katherine Borges, Jim Bartlett, David Dowell, Paul Woodbury and me to name a few. I will be giving my updated talk on DNA Triangulation as well as my Breaking Brick Walls talk. The full schedule is at http://genealogyjamboree.com/2016/schedule-dna.html

Friday morning there are a number of FREE events, including round tables led by experienced researchers both for DNA and genealogy. I will be hosting a DNA table about Triangulation.

The rest of the conference has numerous genealogy talks and a few more DNA presentations plus an exhibit hall of vendors (always one of my favorite parts). Since this is the year I plan to master German genealogy I was pleased to see that it is one of this year’s themes.

A particularly good feature is that you can sign up for a one-to-one consultation with an experienced researcher to help you with one of your genealogical problems, described towards the bottom of this page: http://genealogyjamboree.com/2016/special-events.html

Hope to see you at Jamboree!

Full versus Half Sibling DNA Matches

Recently I was asked whether there is a way to tell a full sibling from a half sibling. Sometimes the total centimorgans are low for one but high for the other. You expect to share about 2550 cM with a full sibling and 1700 with a half sibling; so which is it if you share 2100 cM?

The answer is that full siblings will share many fully identical regions (FIRs), over about 25% of their chromosomes. Half siblings will have no FIRs of any significant size. The exception being some small ones if their parents are from the same population group but still far far fewer than a full sibling.

Here is a comparison of my first eight chromosomes with my brother made at GEDmatch. The green bars are where we are fully indentical.

GEDmatch comparison of me and my brother

GEDmatch comparison of me and my brother (full siblings)

You can click on the image to see the entire display at GEDmatch that this was made from.
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DNA day sales end today!

Dna-splitNational DNA day on April 25 celebrates the day that Crick, Watson, et al published their papers on the structure of DNA. There is an article in Wikipedia about it at https://en.wikipedia.org/wiki/DNA_Day

Both Ancestry.com and Family Tree DNA have been celebrating this date with sales of autosomal DNA test kits that end today. So buy a few!

23andme did not have a sale, but has sent a $50 off coupon out to people who have already tested there as a mother’s day sale or gift and that is good through next Sunday.

See my DNA testing page for a comparison of the sites. Remember that if you test at ancestry you can transfer those results to Family Tree DNA (click here for my post on that with the details)

Ancestry Composition Comparisons: a Case Study

Discovering where your ancestors came from is one of the more popular reasons to do a DNA test but the current ancestry composition algorithms have a long way to go. Sometimes East Asian ancestry is actually American Indian and South Asian might be gypsy or Indian Indian. Scandinavian might be British or North German and British and Irish might be Scandinavian.

Most efforts to analyze the deeper roots of your ancestry are based on samples of modern populations who self report four grandparents of a single ethnicity plus some public databases and a few ancient samples. Since each company relies greatly on their own databases of tested people, it is not surprising to see differences in their predictions.

My brother's Ancestry as shown at DNA.land

My brother’s Ancestry as shown at DNA.land

Since my brother is tested at all three companies I thought I would post the images of what each company sees in his DNA as well show the new report from DNA.land and a few from GEDmatch (both using his uploaded Ancestry.com DNA data). We are confident of our recent ancestry: 50% Southern Norwegian, 25% Bavarian German and 25% Ashkenazi.

The new DNA.land report is shown above, Hmmm, only 16% Ashkenazi.

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