13 Things to Know About DNA Testing Kits

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The search for our identities—where we came from, what we're made of—is a unifying human experience, and our collective fascination with ourselves as individuals has fueled a booming industry around personal DNA testing. More than 12 million people have had their DNA tested by services like 23andMe and AncestryDNA, and that number is expected to grow substantially in the next few years. But can DNA tests really reveal the nuanced information about ancestry and health that many of us seek? Here are 13 things to know about these personal testing kits.

1. PERSONAL DNA TESTING IS SIMPLE—ALL IT TAKES IS A LITTLE SPIT.

Typically, all you have to do is collect some of your saliva or swab the inside of your cheek, then seal the sample in a container and mail it to the lab in a pre-labeled envelope or box. Six to eight weeks later, you can see the results online.

Most personal DNA tests are relatively affordable: Kits from industry leaders like 23andMe, AncestryDNA, Family Tree DNA, MyHeritage DNA, and Living DNA range from $69 to $199. In some cases, the price depends on which genetic reports a customer opts to receive: For 23andMe, for instance, a test that only aims to analyze your ancestry is cheaper than one that also includes health information. Check out this Wiki chart from the International Society of Genetic Genealogy to compare companies' offerings.

2. THE KITS LOOK FOR GENETIC VARIATIONS CALLED SINGLE NUCLEOTIDE POLYMORPHISMS.

After extracting DNA from your cheek swab or saliva sample, DNA testing companies search your DNA for certain genetic variants. The building blocks of DNA are chemical bases called nucleotides, which come in four varieties—A, T, C, and G (adenine, thymine, cytosine, and guanine, respectively). We have 3 billion pairs of these bases, so 6 billion letters in all, strung together in a sequence. Altogether, this genetic information is called your genome.

DNA testing companies determine which of the four letters is present at many locations in your genome. Much of the sequence is shared among humans, so the companies focus on specific letters that vary from person to person, known as single nucleotide polymorphisms (SNPs). Many SNPs have some biological relevance. For example, having one variant of a specific SNP near the gene OCA2, which codes for a protein believed to be involved in producing the dark pigment melanin, makes it much more likely you’ll have blue or green eyes. Other traits and even some diseases are also associated with certain SNPs, some more strongly than others.

3. KIT ACCURACY CAN VARY BASED ON TESTING METHODS.

According to company spokesperson Scott Hadly, 23andMe can identify SNPs with 99.9 percent accuracy, which is in a plausible range for the methods they use. Since many other major companies use similar techniques, their accuracy may be about equivalent—but not all tests meet the same standards. Recently, one test failed to recognize that a purportedly human DNA sample actually came from a golden retriever named Bailey. It did recommend, though, that based on her genetics, Bailey should take up cycling and basketball. The canine’s results came from the lighthearted Superhero DNA Test, which claims to tell customers about their strength, speed, and intelligence. It only tests for four genetic variants, while the pricier kits can include tens of thousands of variants. (It's also worth noting that no matter how many variants a kit tests for, it can't predict complex traits like intelligence, which are influenced by many different genes and environmental factors.)

You should steer clear of companies that offer dubious predictions about your optimal diet, what sports you'll be good at, and other questionable tips. Experts say using DNA tests to extrapolate this information is at best premature and at worst pseudoscience, especially because the recommendations are often based on just a handful of studies on specific groups of people, commonly white men. "The results that have been acquired in one population are not always generalizable to other populations," Jason Rosenbaum, an assistant professor at the University of Pennsylvania's medical school, tells Mental Floss.

4. DNA CAN REVEAL GENETIC CONNECTIONS—BUT INFORMATION ON SOME POPULATIONS IS LIMITED.

Companies use various methods to determine ancestry, but the tests generally involve comparing the customer's DNA to reference DNA meant to represent populations from different geographical regions. Since most people have at least somewhat mixed heritage, ancestry is often represented in percentages: 26 percent Polish, 14 percent Greek, and so on.

These tests aren’t able to guarantee where your ancestors actually lived—they can’t directly compare your data to DNA from people who lived hundreds of years ago, as Adam Rutherford, a British geneticist, pointed out to Gizmodo. And not all groups of people are equally represented in the reference populations, which can impact how precise your results are. People with European backgrounds are overrepresented in the reference data, while there are fewer references relevant to those whose roots lie in the Middle East or Asia, for example. But as research is done on a more diverse range of people, companies are tweaking their analyses to provide more detailed ancestry information to people from all over the world.

5. SOME HINT AT YOUR DNA'S DISTANT HISTORY—INCLUDING NEANDERTHAL HERITAGE.

All humans alive today can trace their mitochondrial lineage back to one woman nicknamed Mitochondrial Eve, who may have lived in Africa about 150,000–200,000 years ago (although this is a source of perennial debate). She wasn't the first modern human woman or the only woman living at the time; other women from her time also have descendants today. They just don’t have an unbroken line of female descendants like Mitochondrial Eve does.

We inherit our mitochondria—the parts of our cells that make energy—from our mothers. Some companies offer a mitochondrial DNA test that allows you to find your maternal haplogroup, which includes people who all share a maternal ancestor thousands or tens of thousands of years ago.

Men can learn about their paternal line through the Y chromosome, which is passed from father to son; certain SNPs on the Y chromosome can be used to determine a person's paternal haplogroup. (Women can find their paternal haplogroup through their biological father or brother.) There’s a "Y-chromosomal Adam," too, although scientists disagree about whether he lived around the same time as Mitochondrial Eve.

A home DNA test might even tell you that you're a little bit Neanderthal, which is especially common in Caucasian and Asian people. Don't worry about Neanderthals' reputation as dull brutes. We now know they were intelligent, used tools, and had their own complex culture.

6. YOU COULD FIND RELATIVES YOU DIDN'T KNOW YOU HAD.

Many DNA testing services allow customers to see whether other users of the same service are biologically related. This can be a boon for anyone assembling a detailed family tree, as well as any adoptees wondering about their biological families. Several people have discovered siblings they never knew they had through these services. In one case, two women—one adopted through an agency and another adopted by a family who found her in the woods as a baby—realized they were long-lost sisters.

Not everyone is pleased to uncover family secrets, though, and you should proceed with caution before you allow a company to match you with new relatives.

7. DNA TESTS CAN REVEAL HEALTH INFORMATION …

While genetic testing might reveal your inability to detect the unique odor of asparagus pee, most people are seeking deeper information, such as whether they have genetic variants associated with diseases like Alzheimer's or breast cancer.

Genetic risk is all about probability. For example, it may be frightening to learn you have an SNP associated with a tenfold increase in risk for a disease—but if that disease only affects 0.01 percent of people, your risk is still just 0.1 percent. Even if you have a SNP strongly associated with a more common illness and show signs of having it, you should see a doctor to get a proper evaluation.

And having a disease-associated SNP isn't a diagnosis. Rare variants are especially likely to lead to false positives: if a variant is only found in one in a million people, it’s more likely that the positive test result is an error than it would be with a more common variant. Some companies report on genetic variants that doctors and scientists haven't deemed medically useful to test for—which is why combing over every SNP is of dubious use. Shoumita Dasgupta, an associate professor in the biomedical genetics program at Boston University, tells Mental Floss that healthcare providers often don't order tests for these SNPs "because professionals have come to the conclusion that the predictive value of these tests is limited."

8. … INCLUDING YOUR RISK OF CERTAIN KINDS OF CANCER.

In March 2018, the FDA granted 23andMe permission to give customers information about certain mutations in the genes BRCA1 and BRCA2 that dramatically increase the risk for breast and ovarian cancer. Some people with a faulty BRCA gene take precautions to prevent or detect cancer early, including undergoing preventive double mastectomies, as Angelina Jolie famously did in 2013.

An important caveat: This test only screens for three SNPs in the BRCA genes that are connected to a dramatic increase in the risk of developing cancer. A positive result merits a consultation with doctor, but a negative result doesn't necessarily mean you're free from the risk of cancer, hereditary or not.

9. SOME DNA TESTING KITS ARE PRESCRIPTION ONLY.

GeneSight is designed to reveal what psychiatric medications will work best for a particular patient. Fertilome aims to show whether a person has genetic markers associated with increased risk of fertility problems, and is intended to help people make reproductive decisions such as whether to freeze eggs or try another round of in vitro fertilization. However, both Fertilome and GeneSight have faced criticism from experts who say there's not enough evidence that the tests are clinically valuable. They're also expensive: Fertilome costs $950, while GeneSight can cost several hundred dollars (though the price can drop to zero with certain insurance plans).

10. MORE DATA ISN'T ALWAYS BETTER.

With the price of DNA analysis falling rapidly, some companies are offering to analyze the order of all the letters of a customer's DNA—what's called sequencing—rather than just looking at SNPs. Sequencing is important in research and medicine: Dasgupta says she now sees some physicians ordering full sequences of multiple genes or even whole exomes (the protein-coding sequences in the genome) for patients.

Exome sequencing is useful to doctors and scientists because it allows them to look for genetic variants beyond the commonly tested SNPs. But every test has a risk of generating false positives, so excessive testing means an increased risk that a person will receive an incorrect diagnosis. Rosenbaum likens it to MRIs. "It's one reason why we don't just give MRIs to everyone, because you're going to turn up things that lead you to believe there's disease where there isn't disease," he explains.

11. YOUR DNA RESULTS COULD CONTRIBUTE TO RESEARCH.

Some home DNA testing companies ask customers to participate in research, answering questions about everything from their sleep habits to their personalities. The goal is to discover previously unknown associations between genetic variants and specific traits. "The way many genetic studies are designed, the more people who are recruited to the study, the more likely the study will be able to identify genetic factors that impact the trait or condition being studied," Dasgupta says.

Personal DNA testing companies potentially have access to the genetic data of millions of users, giving them a huge opportunity to make these connections. Using customer-provided data, 23andMe has already reported some preliminary discoveries on genetic variants linked to detached earlobes, the risk of Parkinson's disease, and more. Studies based on self-reported information always come with caveats, but they’re common in many fields of research and especially useful when collecting objective data isn't practical or possible. Future research spurred by these observations will reveal whether crowdsourced research like 23andMe's has potential to become part of geneticists' repertoire.

12. YOU COULD POTENTIALLY EARN MONEY FROM YOUR DNA.

One company, Genos, charges $499 to sequence a customer's entire exome, and then offers to connect them with genetic researchers. Participating research partners can offer $50 to $250 to Genos users for completing a study intended to find links between their genetic information and any trait or condition the researchers are studying, including dementia, cancer, and infectious disease. Meanwhile, the newly formed company Nebula proposes to sequence customers' genomes, secure them with blockchain technology, and allow customers to control the data—including selling it to biotech and pharmaceutical companies in exchange for Bitcoin-like cryptocurrency. There’s still potential for privacy issues, however, since there’s no guarantee companies that rent or purchase genetic data will keep it secure.

13. YOUR DNA MIGHT ONE DAY HELP TO CATCH A CRIMINAL.

Recently, police investigators in California arrested a man suspected to be the Golden State Killer, thought to be responsible for dozens of rapes and burglaries and at least 12 murders in California from 1976 to 1986. The suspect left DNA behind at the scene of a 1980 murder; after having the DNA analyzed, the investigators created a fake profile on the genealogy website GEDMatch and uploaded the data, hoping it would turn up some of the killer's relatives. It did—and with the help of genealogy experts, the investigators followed the genetic trail to the Sacramento home of 72-year-old Joseph James DeAngelo, who was a cop during the first several years of the deadly crime spree.

The case has raised ethical and privacy concerns for some experts. Genetic data can be stored indefinitely, and it’s possible to use a person's DNA to make inferences about biological relatives who haven’t even taken DNA tests.

Here’s What You Need to Know About the New Coronavirus

jarun011/iStock via Getty Images
jarun011/iStock via Getty Images

This morning, the Centers for Disease Control and Prevention (CDC) confirmed the second case of the recently discovered coronavirus in the U.S. Find out what it is, where it is, how to avoid it, and all the other need-to-know information about the illness below.

What is the new coronavirus?

Coronaviruses are a group of viruses named for the crown-shaped spikes that cover their surfaces (corona is the Latin word for crown). According to the CDC, human coronaviruses can cause upper-respiratory tract illnesses, including the common cold, and can sometimes lead to more severe lower-respiratory tract issues like pneumonia or bronchitis.

Because this latest coronavirus, 2019-nCoV, is so new, health officials are currently trying to figure out how it works and how to treat it. It’s not the first time a potent new coronavirus has caused an international outbreak: SARS-CoV originated in Asia and spread to more than two dozen countries in 2003, and MERS-CoV first infected people in Saudi Arabia before spreading across the globe in 2012.

Where is the coronavirus outbreak happening?

The majority of cases are in China, which counts more than 800 confirmed diagnoses. Most are in Wuhan, a city in China’s Hubei province where 2019-nCoV was first detected last month. Additional cases have been reported in South Korea, Japan, Singapore, Hong Kong, Macao, Taiwan, Thailand, and Vietnam.

The CDC has confirmed two U.S. cases—a man in his thirties outside Seattle, and a 60-year-old woman in Chicago—both of whom had recently returned from trips to Wuhan. A CDC official said another 63 potential cases are being investigated in 22 states, and airports in New York, Chicago, Los Angeles, Atlanta, and San Francisco are conducting health screenings on passengers arriving from China.

Chinese officials have shut down transportation to and from Wuhan. Tourist spots like Beijing’s Forbidden City, Shanghai Disneyland, and a portion of the Great Wall are also closed temporarily.

What are the symptoms of the new coronavirus?

Symptoms are similar to those caused by a cold or the flu, including fever, dry cough, and breathing difficulty. The New York Times reported that as of Friday morning, 25 people in China have died from the virus, and most of them were older men with preexisting health conditions like cirrhosis, diabetes, and Parkinson’s disease.

How does the new coronavirus spread?

Because most of the early cases of 2019-nCoV were traced back to a seafood and meat market in Wuhan, health officials think the virus originally spread from infected animals to humans, but it’s now being transmitted from person to person.

Though scientists are still studying exactly how that happens, the leading theory is that it travels in tiny droplets of fluid from the respiratory tract when a person coughs or sneezes.

How do you avoid the new coronavirus?

The CDC is warning everyone to avoid any nonessential trips to Wuhan, and to avoid animals or sick people if you’re traveling elsewhere in China. If you’ve been to China in the last two weeks and experience any of the symptoms listed above, you should seek medical attention immediately—and you should call the doctor’s office or emergency room beforehand to let them know you’re coming.

Otherwise, simply stick to the precautions you’d normally take when trying to stay healthy: Wash your hands often with soap and water, cover your nose and mouth when coughing or sneezing, stay away from sick people, and thoroughly cook any meat or eggs before eating them.

Should you be worried about the new coronavirus?

The global health community is taking 2019-nCoV seriously in order to curb the outbreak as quickly as possible, but you shouldn’t panic. The CDC maintains that it’s a low-risk situation in the U.S., and public health officials are echoing that message.

“We don’t want the American public to be worried about this, because their risk is low,” Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told USA Today.

[h/t USA Today]

Has An Element Ever Been Removed From the Periodic Table?

lucadp/iStock via Getty Images
lucadp/iStock via Getty Images

Barry Gehm:

Yes, didymium, or Di. It was discovered by Carl Mosander in 1841, and he named it didymium from the Greek word didymos, meaning twin, because it was almost identical to lanthanum in its properties. In 1879, a French chemist showed that Mosander’s didymium contained samarium as well as an unknown element. In 1885, Carl von Weisbach showed that the unknown element was actually two elements, which he isolated and named praseodidymium and neodidymium (although the di syllable was soon dropped). Ironically, the twin turned out to be twins.

The term didymium filter is still used to refer to welding glasses colored with a mixture of neodymium and praseodymium oxides.

One might cite as other examples various claims to have created/discovered synthetic elements. Probably the best example of this would be masurium (element 43), which a team of German chemists claimed to have discovered in columbium (now known as niobium) ore in 1925. The claim was controversial and other workers could not replicate it, but some literature from the period does list it among the elements.

In 1936, Emilio Segrè and Carlo Perrier isolated element 43 from molybdenum foil that had been used in a cyclotron; they named it technetium. Even the longest-lived isotopes of technetium have a short half-life by geological standards (millions of years) and it has only ever been found naturally in minute traces as a product of spontaneous uranium fission. For this reason, the original claim of discovery (as masurium) is almost universally regarded as erroneous.

As far as I know, in none of these cases with synthetic elements has anyone actually produced a quantity of the element that one could see and weigh that later turned out not to be an element, in contrast to the case with didymium. (In the case of masurium, for instance, the only evidence of its existence was a faint x-ray signal at a specific wavelength.)

This post originally appeared on Quora. Click here to view.

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