Hollis Johnson
  • Investigators say they cracked the cold case of the Golden State Killer with help from data on a genetics website.
  • The investigators revealed that they uploaded a suspect’s raw DNA signature – sourced from an old crime scene sample – to a site called GEDmatch.
  • The case has raised privacy concerns among people who have submitted their DNA data to similar genetics sites.
  • Here’s how to delete your DNA and data from 23andMe, Ancestry, and Helix.

The recent arrest in one of California’s most infamous serial-killer cases was based in large part on a DNA sample submitted to a genetics website by a distant relative of the suspect.

If that news has you concerned about the security of your own genetic material, you may be wondering how to delete it from genetic databases kept by popular genetics testing companies like 23andMe and Ancestry.

Those two databases were not used by investigators to track down Golden State Killer suspect Joseph James DeAngelo. Instead, investigators used a service called GEDmatch, which lets customers upload a raw DNA signature. Investigators created a profile for the suspect using DNA sourced from a long-stored crime scene sample, and found matches between DeAngelo’s crime scene DNA and the DNA of a distant family member.

23andMe, Ancestry, and Helix (National Geographic’s genetics service) only accept saliva samples for genetics testing – an easy way of obtaining DNA. But a similar company called Family Tree DNA could likely accept hair or blood, according to Joe Fox, an administrator for one of the company’s surname projects.

Whichever way a company gets your DNA, privacy advocates say there’s cause for concern. Although genetic data is ostensibly anonymized, companies can and do sell your data to third parties like pharmaceutical companies. From there, it could find its way elsewhere, advocates say.

Here’s how to delete your data from a few of these services.

23andMe could keep your spit and data for up to 10 years


23andMe Instagram

The core service provided by most commercial genetic tests is built on the extraction of your DNA from your spit – that’s how you get the results about your health and ancestry information.

After registering your spit sample online with 23andMe, the company will ask if you’d like your saliva to be stored or discarded. But you are not asked the same question about your raw genetic data – the DNA extracted from your spit.

Based on the wording of a document called the “Biobanking Consent Document,” it’s a bit unclear what happens to that raw DNA once you decide to have the company either store or toss your spit.

Here’s the statement’s exact language:

“By choosing to have 23andMe store either your saliva sample or DNA extracted from your saliva, you are consenting to having 23andMe and its contractors access and analyze your stored sample, using the same or more advanced technologies.”

That leaves a bit of a grey area as far as what 23andMe has the ability to keep, and how they can use your DNA information. If your spit or DNA sample is stored, the company can hold onto it for between one and 10 years, “unless we notify you otherwise,” the Biobanking Consent Document states.

Still, you can request that the company discard your spit. To do so, go to its Customer Care page, navigate to “Accounts and Registration,” scroll to the bottom of the bulleted list of options, and select the last bullet titled “Requesting Account Closure.”

Once there, you must submit a request to have your spit sample destroyed and/or have your account closed.

Ancestry won’t toss your spit unless you call, but you can delete your DNA results


Sarah Kimmorley/Business Insider Australia

If you want to delete your DNA test results with Ancestry, use the navigation bar at the top of the homepage to select “DNA.”

On the page with your name at the top, scroll to the upper right corner, select “Settings,” then go to “Delete Test Results” on the right side column.

According to the company’s latest privacy statement, doing this will result in the company deleting the following within 30 days: “All genetic information, including any derivative genetic information (ethnicity estimates, genetic relative matches, etc.) from our production, development, analytics, and research systems.”

But if you opted into Ancestry’s informed “Consent to Research” when you signed up, the company says it can’t wipe your genetic information from any “active or completed research projects.” It will, however, prevent your DNA from being used for new research.

To have the company discard your spit sample, you must call Member Services and request that it be thrown out.

Helix will discard your spit upon request, but may keep data ‘indefinitely’

In its most recently updated Privacy Policy, Helix states that it may “store your DNA indefinitely.”

It also keeps your saliva sample, but you can request that it be destroyed by contacting Helix’s Customer Care via a request form that looks similar to 23andMe’s.

Maybe you got one of those find-your-ancestry kits over the holidays. You’ve sent off your awkwardly collected saliva sample, and you’re awaiting your results.

If your experience is anything like that of me and my mum, you may find surprises – not the dramatic “switched at birth” kind, but results that are really different from what you expected.

My mum, Carmen Grayson, taught history for 45 years – secondary school and university – retiring from Hampton University, Virginia, United States, in the late 1990s.

But retired history professors never really retire, so she has been researching her family’s migrations, through both paper records and now a DNA test.

Her father was French Canadian, and her mother (my namesake, Gisella D’Appollonia) was born of Italian parents who moved to Canada about a decade before my grandmother was born in 1909.

Last fall, we sent away to get our DNA tested by Helix, the company that works with National Geographic. Mum’s results: 31% from Italy and Southern Europe. That made sense because of her Italian mother.

But my Helix results didn’t even have an “Italy and Southern European” category.

How could I have 50% of Mom’s DNA and not have any Italian? We do look alike, and she says there is little chance I was switched at birth with someone else.

We decided to get a second opinion and sent away to another company, 23andMe. We opened our results together and were just as surprised.

This time, I at least had a category for southern Europe. But Mum came back as 25% southern European, me only 6%.

And the Italian? Mum had 11.3% to my 1.6%. So maybe the first test wasn’t wrong.

But how could I have an Italian grandmother and almost no Italian genes?

To answer this question, mum and I drove up to Baltimore to visit Dr Aravinda Chakravarti of the Johns Hopkins University School of Medicine and the Bloomberg School of Public Health, who has spent his career studying genetics and human health.

“That’s surprising,” he told us when we showed him the results. “But it may still be in the limits of error that these methods have.”

The science for analysing one’s genome is good, Dr Chakravarti said. But the ways the companies analyse the genes leave lots of room for interpretation.

So, he said, these tests “would be most accurate at the level of continental origins, and as you go to higher and higher resolution, they would become less and less accurate”.

As in my case, the results got me to Europe, just not Italy. My 23andMe test also showed less than 1% of South Asian, Sub-Saharan African, and East Asian and Native American.

This, Dr Chakravarti said, is likely true because the genetics of people on a continental level are so different, and it’s not likely that South Asian will look like European.

“Resolving a difference between, say, an African genome and an East Asian genome would be easy,” he said. “But resolving that same difference between one part of East Asia and another part of East Asia is much more difficult.”

I also learned that even though I got half of my genes from mum, they may not mirror hers.

DNA, genes, ancestry, DNA test, lineage, Gisele Grayson, Carmen Grayson,

As mother and daughter, Carmen Grayson (left) and Gisele thought their DNA ancestry tests would be very similar. Boy, were they surprised. — TNS

We do inherit our genes – 50% from each parent. But Elissa Levin, a genetic counsellor and the director of policy and clinical affairs of Helix, says a process called recombination means that each egg and each sperm carries a different mix of a parent’s genes.

“When we talk about the 50% that gets inherited from mum, there’s a chance that you have a recombination that just gave you more of the northwest European part than the Italian part of your mum’s ancestry DNA,” she said.

That is also why siblings can have different ancestry results.

The companies compare customers’ DNA samples to samples they have from people around the world who have lived in a certain area for generations.

The samples come from some databases to which all scientists have access, and the companies may also collect their own.

“We’re able to look at, what are the specific markers, what are the specific segments of DNA that we’re looking at that help us to identify, ‘Those people are from this part of northern Europe or southern Europe or South-East Asia’,” Levin said.

As the companies collect more samples, their understanding of markers of people of a particular heritage should become more precise.

But for now, the smaller the percentage of a population within a continent that is in the database, the less certain they are. Helix chooses not to report some of those smaller percentages, Levin said.

23andMe reports results with a 50% confidence interval – they’re 50% sure their geographic placement is correct.

Move the setting up to 90% confidence, meaning your placement in a region is 90% certain, and that small 1.6% of my ancestry that is Italian disappears.

The ancestry tests also have to take into account the fact that humans have been migrating for millennia, mixing DNA along the way.

To contend with that, the companies’ analyses involve some “random chance”, as Levin put it. A computer has to make a decision.

And the ancestry companies have to make judgment calls. Robin Smith, a senior product manager with 23andMe, said their computers compare the DNA with 31 groups.

“Let’s say a piece of your DNA looks most like British and Irish, but it also looks a little bit like French-German,” he said. “Based on some statistical measures, we’d decide whether to call that as British-Irish or French-German, or maybe we go up one level and call it northwestern European.”

What does he think explains my case?

“It was a bit surprising,” he said. “But in looking at the fact that you have some southern European and some French-German, the picture became a little clearer to me.”

So, for now, my Italian grandmother doesn’t show up in these tests.

No matter – Dr Chakravarti, Levin and Smith all say to let the results add to your life story. The DNA is just a piece of what makes you, you. – Kaiser Health News/Tribune News Service