- Yulia Mayorova/Shutterstock
- Genealogy and DNA site Ancestry once partnered with Google’s stealthy life-extension spinoff, a company called Calico, to study the genetics of longevity.
- The new study suggests that our genes play less of a role in how long we live than previously believed.
- Instead, traits and behaviors that include everything from diet and exercise to friendliness appear to play a strong role in longevity.
- But surprisingly, we still pass these traits on through generations – mostly by picking partners who look and act like us, the researchers suggest.
The road to achieving a long life is littered with hype. The usual life-extension suspects include pricey pills and supplements; the peculiar involve infusions of young blood and chambers pumped with sub-zero temperatures.
Then there’s science. And one scientific factor that has long been presumed to dictate much of how long we live is our DNA. For decades, it was assumed that the genes we inherit from our parents explain anywhere from 15% to 30% of the variations in longevity that are observed between people.
But a new study that came from quiet collaboration between genetics company Ancestry and a Google life-extension spinoff called Calico suggests that our genes play less of a role in our lifespan than we thought.
Instead, traits and behaviors that include everything from diet and exercise to friendliness appears to play a strong role in longevity. Surprisingly, we still pass these traits on through generations – mostly by picking partners who look and act like us, the researchers report.
In essence, the findings suggest that people effectively transfer longevity from one generation to the next much in the same way that wealth and socioeconomic status are passed from parents to children: by choosing partners with attitudes and attributes that mirror our own, regardless of how different their DNA may be.
Picking partners who act and think like us
- seyfettin dincturk / Unsplash
For decades, researchers studying longevity and genetics had estimated that the genes we inherit from our parents play a significant role in determining how long we live. Previous studies suggested that genes account for as much as 30% of the total variability in lifespan between individuals.
But the new study from Ancestry and Calico indicates that our DNA may be much less important in determining longevity than traits and behaviors like diet, exercise, and personality. After looking at data from more than 54 million family trees and the birth and death information for over 400 million individuals, the researchers concluded that our DNA accounts for less than 10% of lifespan variability.
Instead, we pass on longevity through generations by choosing partners whose attitudes and attributes look much like our own. In research parlance, that’s known as “assortative mating.”
“The true heritability of human longevity for birth cohorts across the 1800s and early 1900s was well below 10%, and … has been generally overestimated due to the effect of assortative mating,” the scientists wrote.
Put another way, we tend to pick partners with attitudes and attributes – from eating and exercising to friendliness – that mirror our own. And as a result, we tend to live similar amounts of time, and have children who do as well.
How friendly we are and how often we work out may play a stronger role in our longevity than our DNA
Previous studies shed light on how important lifestyle factors are when it comes to how long we live. In a recent study published in the journal Circulation, for example, scientists pinpointed five lifestyle factors that appear to be linked with a significantly longer lifespan, judging by the outcomes of two long-term studies that involved about 123,000 adults.
People in the study who lived long lives tended to:
- Do at least 30 minutes of cardio exercise every day.
- Eat a Mediterranean diet.
- Never smoke.
- Stick to a healthy body weight.
- Drink no more than 1-2 alcoholic beverages a day.
As part of several other recent studies, scientists have uncovered a handful of personality traits that also appear to be strongly linked to longer-than-average lives. They include:
Taken together, the findings suggest that how long we live may be less a matter of what we’re born with than the circumstances in which we live and the choices that we make. Those choices, as the Ancestry and Google researchers acknowledge in their new paper, tend to be based on everything from social status to wealth and then, just like genetics, passed on from one generation to the next.
- American Cancer Society/Getty Images
- Bold headlines linking blockbuster gene-editing tool CRISPR to cancer sent stocks in companies trying to bring the technology to medicine tumbling.
- But scientists who study the technique say the concerns are overblown at best and an incorrect interpretation of the science at worst.
- Ultimately, using CRISPR does not appear to present any challenges that scientists familiar with gene editing have not already faced.
Earlier this week, reports linking the blockbuster gene-editing tool CRISPR to cancer in two studies sent investors scrambling to pull out of companies working on the technology, which is being studied for use in everything from food to medicine. The tool’s precise cut-and-paste approach to gene editing allows for a range of promising medical applications, from curing sickle cell anemia to preventing some forms of blindness.
On Monday afternoon, headlines suggested that cells edited with the tool were more likely to become cancerous. Within hours of the reports being published, shares of Editas Medicine, CRISPR Therapeutics, Intellia Therapeutics, and Sangamo Therapeutics – all of which are trying to bring CRISPR to medicine – took a significant tumble.
But scientists who study CRISPR and other methods of gene editing call the reports “overblown.” They say the link to cancer is tenuous at best and an incorrect interpretation of the results at worst.
“This is absurd,” John Doench, the associate director of the genetic perturbation platform at MIT’s Broad Institute, told Business Insider. “There was a massive overreaction here.”
Like many other researchers involved in the space, Doench read the two studies highlighted in the recent report and published in the journal Nature Medicine. Instead of concluding that the technique causes cancer, Doench read the papers and thought it highlighted facts about how cells behave in response to perceived threats. Most of these are already fairly well-known to people who study gene editing. Tweaking a cell’s DNA is a violent process; when it is done, cells respond by trying to defend or repair themselves. This is one of the biggest hurdles facing most cutting-edge gene editing approaches today. It is not unique to CRISPR.
“I’m honestly trying to figure out why this has generated such a response and I really can’t,” Doench said. “Everything I can see is just related to the stocks and finances and not in anyway related to the science.”
Cells responding normally to a perceived threat
- Samantha Lee/Business Insider
The problem comes down to the basic biology of what happens in cells that encounter DNA damage.
To make changes to DNA, CRISPR breaks key parts of the strands that make up the genetic material in a cell. This cutting and slicing ability is why it’s so powerful; previous tools for gene modification were limited by their inability to precisely target certain parts of a cell’s DNA.
When anything – be it CRISPR or a disease or anything else – slices into genetic material, the “broken” cells try to patch themselves up in a process that’s governed largely by a gene called p53.
If that fix-it gene starts to malfunction, it means cells can’t self-repair. Cancer can occur as a result.
The recent papers did not reveal that editing the DNA of a cell with CRISPR damaged its fix-it genes. Instead, the process appeared to activate them, which is exactly what scientists would expect to happen with many kinds of gene-editing.
In other words, CRISPR turned on the self-repair process, and “the cell is responding as it should,” Doench said.”That doesn’t mean p53 has been inactivated and these cells are now cancerous, it means the cell has done its job.”
A tweet that Nature sent out on Tuesday afternoon with a link to one of the papers appeared to back up this interpretation, saying, “p53 defends against CRISPR-Cas9 genome editing.”
Gaetan Burgio, a professor of genetics who studies CRISPR at the Australian National University, agreed, tweeting, “Beware exaggeration and overstated headlines. The papers say after CRISPR-Cas9 … P53 signaling is activated. They don’t say CRISPR could cause cancer.”
Laboratory cells acquire all kinds of mutations, gene-editing or not
The scientists behind the two recent papers were looking out for another potentially disturbing consequence of using CRISPR on these cells: that their fix-it genes would be shut down after applying the tool – a result that would leave them vulnerable to mutations and cancer.
But that didn’t happen either, according to the two papers. What did happen, however, is that the cells edited with CRISPR were more likely to have mutations on their fix-it genes. But that wasn’t necessarily a result of CRISPR.
In fact, cells in labs have a tendency to acquire all kinds of mutations simply as a result of being in a lab. A 2017 paper published in Nature found, for example, that human embryonic stem cell lines frequently develop mutations without any kind of gene editing being done on them. Many of those mutations also happen to be on the p53, or fix-it, gene.
The last line of one of the most recent papers sums this idea up well, concluding that scientists who are developing techniques using CRISPR should closely monitor the function of the fix-it gene on the cells that they edit using the technique.
This is also something that most biologists – especially those who work in gene editing – already know. Other techniques like zinc finger nucleases, a type of gene editing that can lead to outcomes seen as similar to CRISPR, require keeping a close eye on the fix-it gene, too. That’s a risk scientists are actively monitoring, not a unique issue presented by CRISPR.
“To anyone who would actually use gene editing, this was already baked into the cake,” Doench said.
- A spit sample for a DNA test.
- Hollis Johnson
- I tried DNA tests from 23andMe, Ancestry, and National Geographic to learn about my family’s history and my health.
- The tests vary in terms of what information they provide and how precise they are.
- I’m often asked which test I’d recommend. My answer boils down to one question: What do you want to get out of the test?
- From migration patterns, to how much DNA you have in common to a Neaderthal, here’s what you can learn from each report.
I’ve sent my spit off for more genetics tests than anyone else I know.
The tests analyzed the DNA in my saliva to find out a host of different things about my ancestry and health.
Genetic testing companies have proprietary sets of data and various ways of analyzing information, so each one I tried offered a distinct approach. One provided details about my great-grand relatives, while others listed how much Neanderthal DNA I have.
Every so often, someone asks me which test I recommend. And my answer boils down to one question: What do you want to get out of the test?
Let’s compare three direct-to-consumer tests: AncestryDNA, 23andMe, and National Geographic’s Geno 2.0 test.
23andMe gave me a comprehensive picture of my health and ancestry that keeps growing
- Lydia Ramsey/Business Insider
23andMe currently offers two versions of its test: The $199 version comes with health and ancestry components, whereas the $99 version just has the ancestry test.
To analyze your DNA, 23andMe uses a technique called genotyping. Humans have 3 billion base pairs of DNA in our genome – that’s a lot of information to sift through – so genotyping technology looks for specific parts of DNA and pieces them together.
The health reports can tell you information about your physical traits (like if you’re likely to have dimples or curly hair), wellness (how well you metabolize caffeine or if you’re a sprinter), and carrier status for certain genetic mutations.
The FDA now allows 23andMe to provide reports on a person’s genetic risk for certain diseases, including Alzheimer’s and Parkinson’s diseases. In total, the test now has more than 74 reports, and more get added all the time. I often get emails telling me that a new test is ready for me – recently I got one that looks at my genetic health risk for celiac disease.
With 23andMe’s ancestry reports, users have access to information about their ancestry composition (which geographic regions your genes align with), haplogroups (genetic populations that share a common ancestor), and Neanderthal ancestry. They also get access to something called a DNA Relatives tool, which 23andMe users can opt into to connect with other users and find out whether they have relatives in the system.
In February, 23andMe updated its ancestry reports to provide more specific regional information. My report used to specify just Scandinavian ancestry, but now specifies Norway as a country where my ancestors lived within the past 200 years. The company also maps out how many generations ago you may have had ancestors from a particular region. For example, I may have had a Finnish ancestor sometime in the mid-to-early 1800s or late 1700s, while my French and German ancestors date even earlier.
Verdict: If you’re looking at this test as a science experiment, using it as a way to get involved in research, or viewing it as a chance to learn about your genetic health risks, then this is a fit for you. (Though if you opt for the full test, there are some considerations patient groups and genetic counselors would like users to take into account.)
If you just want to know your ancestry percentages – especially now that they’re more exact – and how much Neanderthal variants you have, the $99 version is a good bet.
AncestryDNA connects the dots between you and your ancestors
- Lydia Ramsey/Business Insider
Ancestry’s test, as its name suggests, is all about family histories and genealogy. You won’t find health and wellness reports in its $99 test, but you will find information about where your family comes from and how that lineage connects you to potential ancestors.
Like 23andMe, Ancestry uses genotyping technology to analyze your DNA. The service also helps you link up your DNA test to a self-reported family tree.
There’s a lot to discover within that data – for example, I was matched up with ancestors dating back to the 18th century, and could explore how I was connected to them.
If you simply want to know, say, what percent Scandinavian you are, Ancestry’s site makes it easy to focus on those numbers. Those who want to dig deep into family trees can do that as well. I would definitely consider purchasing this test for a relative who enjoys researching family history.
Ancestry has also added a DNA story element that maps out your ancestors’ migration patterns. My ancestors started moving to the Midwest in the US around 1825-1850.
Verdict: If the idea of tracing your family tree through the generations and connecting with distant relatives gets you excited – but you’re less interested in health information – this is the test for you.
National Geographic’s test uses next-generation sequencing technology to inform its reports
- Hollis Johnson
National Geographic has an ancestry test called Geno 2.0.
The test – which currently costs $99.95 but originally was $199.95 – is different from AncestryDNA and 23andMe in that it uses next-generation sequencing instead of genotyping technology.
Unlike genotyping, which just looks for specific parts of DNA and pieces them together, next-generation sequencing looks at only the protein-encoding parts of your genome, called the exome. The next-generation sequencing analyzes roughly 2% of those 3 billion base pairs.
The additional information this technique picks up could lead to new, more specific genetic testing features in the future, especially as our knowledge of the genome and exome continues to grow.
- Hollis Johnson
Based on next-generation sequencing, National Geographic’s test provides three ancestry reports.
- Regional, which tells you where your ancestors came from more than 500 years ago. This didn’t get into as many specifics in my case as AncestryDNA and 23andMe’s tests did.
- Deep, which shows your ancestors’ migration patterns thousands of years ago.
- Hominin ancestry, which tells you how much DNA you have in common with a Neanderthal.
The verdict: For what you get, the test doesn’t have nearly the range that other ancestry tests have. And when not on sale, it’s more expensive. National Geographic, however, says the revenue funds nonprofit “conservation, exploration, research, and education” efforts.
Another aspect to take into account when deciding which DNA test to take is the issue of privacy. The tests do, after all, deal with information that’s fundamental and unique to every individual.
In a blog post published December 12, the FTC recommended reading the fine print. “If you’re thinking about buying an at-home DNA test kit, you owe it to yourself – and to family members who could be affected – to investigate the options thoroughly,” it says.
James Hazel, a post-doctoral research fellow at Vanderbilt University’s Center for Biomedical Ethics and Society, has been looking into the privacy policies of consumer genetics tests. He said the FTC’s suggestion is very important.
“We are good at clicking ‘agree’ and not reading the terms of service,” he told Business Insider in December.
Questions to keep in mind when reading through the terms of service include:
- Who owns your DNA?
- Who gets to see your de-identified (not attached to your name) information?
- How is the data that’s tied to your identifiable information used?
- Can you opt out of giving research partners your genetic data?
- Can you wipe your information after taking a test?
There are other ancestry tests I have yet to try
The DNA-testing field is exploding. In the past few years, the number of people taking DNA tests has picked up pace. More than 12 million people have had their DNA sequenced, and almost 10 million of those tests have happened since 2016. With that, there’s likely a growing number of tests emerging that I haven’t had a chance to try.
MyHeritage has a DNA test that’s currently going for $49 (originally $99). Its tests, like Ancestry’s, are focused on building family connections and trees.
Others, like FamilyTree DNA (which offers tests from $59) are also geared toward people who want to find genetic links to relatives.
Each company has its own methods, algorithms, and data, which is why the reports differ. Because the three main direct-to-consumer genetics tests are around the same price, you should go with the one that will answer your most pressing questions.
This post was originally published in April 2017 and has been updated to reflect changes to the DNA tests.