How to find a killer using DNA and genealogy

It was only a matter of time before the methodologies and technologies that have been developed to break genealogical brick walls and find unknown birth parents were used to identify victims and criminals. The use of DNA and genealogy to solve the horrific Golden State killer case has been sensationalized in the media for several days now. I even got a few calls from reporters as a DNA and GEDmatch expert. Also, just two weeks ago an unknown murder victim from 30 years ago, found in Florida, was finally identified from a DNA cousin match on a genealogy site.

Some of my friends and cousins are worried about the possible invasion of their DNA test privacy. Most just want to understand how this can be done, so I will try to explain that in this post. At the end of this post I will include links to other genetic genealogy blog posts that have wrestled with the issues raised.

You share about 98.5% of your DNA with this fellow

Although I have sympathy with the concerns of people who fear false identification using DNA techniques, this is not my fear. The methodology used gets to a pool of possibles whose actual DNA is then collected and compared. I have confidence in that technology. My fear is that my cousins will stop testing their DNA to help my family projects or stop uploading their tests to my favorite tools site, GEDmatch, where the DNA test results from different companies can be compared.

Click here for an article at the LA Times which went into more of the technical details of the Golden State killer case for us genetic genealogists and here for a lengthy video interview with investigator Paul Holes on how it was done.

Let me start my article by reminding all of you that every human’s DNA is about 99% the same as every other human and about 98.5% the same as a chimpanzee. The companies who test your personal genome only test a small sample of that differing 1%. To put it in numbers, our genomes have about 3 billion base pairs and the tests cover about 700,000 of those, which comes out to about .02% of your genome. Not enough to clone you or worry about, in my opinion.

Next let me remind you that uploading your DNA results from Ancestry or 23andme or wherever you tested to GEDmatch does not expose even that little bit of your DNA to the public. What happens is that your “DNA cousins” will match long sections of your data, called segments, and they can see which locations on which chromosome(s) are the same between the two of you. Therefore they know what your actual DNA code is only on those pieces they share with you. When they match you in the GEDmatch database, they can see your email address, name or pseudonym, and your kit number. With that kit number they can see what color your eyes are, what ethnicities various calculators give, and who else you match. If you have connected a family tree to your DNA they can also see the non-living people in your tree. But they have to match your DNA significantly to see any of that! Click here for an article I wrote addressing privacy worries at GEDmatch

So how do you get from there to a killer?
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DNA Day: last chance for sale prices

To celebrate DNA Day, April 25, all the companies which sell personal genome testing kits are having the best sales ever seen. These mainly end at midnight on the 25th. Click here for my page discussing the pluses and minuses of testing with each company.

My quick recommendations are:

  • Test at the largest database, Ancestry.com DNA, if you are interested in genealogy and are from an English speaking country.
  • Test at 23andme if you want the health results and like the nitty gritty segment details.
  • Test older family members and privacy worriers at Family Tree DNA (the cheek swab is easier than spitting, plus they keep the sample and do not sell any results).
  • Europeans or children of recent immigrants may prefer MyHeritage or Family Tree DNA

But what is DNA day and who deems it a day to celebrate? It is the day in 1953 when “James Watson, Francis Crick, Maurice Wilkins, Rosalind Franklin and colleagues published papers in the journal Nature on the structure of DNA” [source wikipedia]

My husband remembers his text books from the 1970s on molecular biology which claimed DNA could never be sequenced. I recently saved his 1970 second edition of Watson’s Molecular Biology of the Gene (now in its 7th edition as of 2013) above from our give-to-charity box.

On April 25, 2003 the human genome project declared success; Fifty years to the day after the Crick, Watson, et al article appeared. Do you think the choice of day was deliberate? And here we are 15 years later where the price of sequencing the small part of your genome which can be different from other humans is only about $50. Amazing!

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MyHeritage DNA Matching: Excellent Enhancements

MyHeritage has kept its promises: tree matching, pedigree display, a place for notes, and best of all, a chromosome browser. Plus the cousin matching is finally quite good, at least for your closer cousins, and includes some triangulation.

A very nice new feature is the Ethnicities Map, a menu item under DNA, which gives you the common groups for any modern day country you select. Since a question I commonly receive from family members is “Why doesn’t my known German ancestry show up?”, it is great to be able to show them this map:

A picture says it better than telling them that in the DNA, northern Germans look Scandinavian, southern Germans look Italian, eastern Germans look East European, and western Germans look French. My maternal ancestors lived at the crossroads of Europe!

Uploading your results from another DNA testing company is still free at MyHeritage and you get many of the DNA features. Personally I have just a data subscription and a small tree (there is a 250 person limit for unpaid members). In a few weeks I will create an account for a cousin and see if this works as well as it is supposed to for completely free members.

After the recent change, the segment details for my matches to my close family are very similar to what I see on GEDmatch and 23andme, same chromosomes, similar sizes, slightly different boundaries. This is a wonderful improvement!

Since my ancestors are all fairly recent immigrants from Norway and Germany, I was hoping for some international matches when I uploaded my DNA results to MyHeritage last year. In practice, as usual, there were no Germans (testing is not popular there), but plenty of Norwegian cousins that I already knew about, plus a few new distant ones.

However, I did recently get a new close cousin match (1C2R-2C1R), Melissa from New Jersey. I will use her match to investigate the new improved DNA matching.
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Which Ancestor Do You Look Like?

When my Dad rode up the elevator in our NYC apartment building, he was often asked if he was my father.
I always thought I looked just like him and just like pictures of his mom, except for my nose which came from my mother’s side.

The other day my brother showed me a cool new tool that compares a picture of yourself to pictures of any ancestors whose photos are in the FamilySearch tree. Needless to say I promptly uploaded every ancestor image I could find!

This tool is called Compare-a-Face and is part of the FamilySearch Discovery suite of tools. It is currently featured on the FamilySearch home page when you log in.

I soon discovered that the original photo of me did not get compared to the new ancestor photos that I had just put there, so I uploaded another one. I had to try several different pictures of me to get the result I wanted from the comparison to my Dad’s mom.

Notice that the images are shown in order of how like you they are: the best on the left to least on the right. You click on any little image at the top to get it front and center with a percentage of simularity.

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This is your life DD Carol!

When DNA Detective (DD) Carol Rolnick showed a family network diagram at her presentation last Saturday a voice suddenly piped up from the back of the room. Amazed, she looked up and said, “Sean?” A foundling whose case she had recently solved had flown in from Texas to come and surprise her. They had never met in person before. He saw on FaceBook that she was speaking in Carlsbad, so he got on a plane. Wow.

Sean left, Teri (a DIG organizer) center, Carol (surprised) right, photo by Kimber Motsinger

What a treat for us at our North County DIG (DNA Interest Group) meeting! Not only did we get Carol’s presentation but we got to hear the story of this case from both her and Sean. She mentioned that she has a special place in her heart for foundlings. They took turns explaining how she used DNA to solve this mystery of a 4 year old boy abandoned so many years ago in a motel room with his 2 year old brother. They knew their first names and not much else.

Sean was absolutely compelling when he spoke. Not a dry eye in the house. Preparation for his book tour?

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