Scientists Remove Disease-Causing Mutations from Human Embryos

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Researchers have successfully edited the genes of viable human embryos to repair mutations that cause a dangerous heart condition. The team published their controversial research in the journal Nature.

The versatile gene-editing technique known as CRISPR-Cas9 is no stranger to headlines. Scientists have already used it to breed tiny pigs, detect disease, and even embed GIFs in bacteria. As our understanding of the process grows more advanced and sophisticated, many researchers have wondered how it could be applied to human beings.

For the new study, an international team of researchers fertilized healthy human eggs with sperm from men with a disease called hypertrophic cardiomyopathy, a condition that can lead to sudden death in young people. The mutation responsible for the disease affects a gene called MYBPC3. It’s a dominant mutation, which means that an embryo only needs one bad copy of the gene to develop the disease.

Or, considered another way, this means that scientists could theoretically remove the disease by fixing that one bad copy.

Eighteen hours after fertilizing the eggs, the researchers went back in and used CRISPR-Cas9 to snip out mutated MYBPC3 genes in some of the embryos and replace them with healthy copies. Three days later, they checked back in to see how their subjects—which were, at this point, still microscopic balls of cells—had fared.

The treatment seemed successful. Compared to subjects in the control group, a significant number of edited embryos appeared mutation- and disease-free. The researchers also found no evidence that their intervention had led to any unwanted new mutations, although it is possible that the mutations were there and overlooked.

Our ability to edit human genes is improving by the day. But, many ethicists argue, just because we can do it doesn’t mean that we should. The United States currently prohibits germline editing of human embryos by government-funded researchers. But there’s no law against such experimentation in privately funded projects like this one.

The same day the new study was published, an international committee of genetics experts issued a consensus statement advising against editing any embryo intended for implantation (pregnancy and birth).

"While germline genome editing could theoretically be used to prevent a child being born with a genetic disease, its potential use also raises a multitude of scientific, ethical, and policy questions,” Derek T. Scholes of the American Society of Human Genetics said in a statement. “These questions cannot all be answered by scientists alone, but also need to be debated by society."

Ethicists and sociologists are concerned by the slippery slope of trying to build a better human. Many people with chronic illness and disability live happy, complete lives and report that they’re limited more by discrimination than by any medical issues.

Disability studies expert Lennard Davis of the University of Illinois says we can’t separate scientific decisions from our society’s history of violence against, and oppression of, disabled and sick people.

“A lot of this terrific science and technology has to take into account that the assumption of what life is like for people who are different is based on prejudice against disability,” he told Nature in 2016.

Rosemary Garland-Thomson is co-director of the Disability Studies Initiative at Emory University. Speaking to Nature, she said we are at a cultural and ethical precipice: “At our peril, we are right now trying to decide what ways of being in the world ought to be eliminated.”

Why Is Pee Yellow?

Chloe Effron
Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Your body is kind of like a house. You bring things into your body by eating, drinking, and breathing. But just like the things we bring home to real houses, we don’t need every part of what we take in. So there are leftovers, or garbage. And if you let garbage sit around in your house or your body for too long, it gets gross and can make you sick. Your body takes out the garbage by peeing and pooping. These two things are part of your body’s excretory system (ECKS-krih-tore-eee SISS-tem), which is just a fancy way of saying “trash removal.” If your body is healthy, when you look in the toilet you should see brown poop and yellow pee.

Clear, light yellow pee is a sign that your excretory system and the rest of your body are working right. If your pee, or urine (YER-inn), is not see-through, that might mean you are sick. Dark yellow urine usually means that you aren’t drinking enough water. On the other hand, really pale or colorless pee can mean you might be drinking too much water! 

Your blood is filtered through two small organs called kidneys (KID-knees). Remember the garbage we talked about earlier? The chemicals called toxins (TOCK-sins) are like garbage in your blood. Your kidneys act like a net, catching the toxins and other leftovers and turning them into pee.

One part of your blood is called hemoglobin (HEE-moh-gloh-bin). This is what makes your blood red. Hemoglobin goes through a lot of changes as it passes through your body. When it reaches your kidneys, it turns yellow thanks to a chemical called urobilin (yer-ah-BY-lin). Urobilin is kind of like food coloring. The more water you add, the lighter it will be. That's why, if you see dark yellow pee in the toilet, it's time to ask your mom or dad for a cup of water. 

To learn more about pee, check out this article from Kids Health. 

Flashing Status Symbols Won’t Impress New Friends—and May Even Backfire

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Trying to keep up with the Joneses isn’t a very effective way of making friends. As The Outline reports, a recent study in the journal Social Psychological and Personality Science suggests that flashing status symbols makes people less likely to want to be your friend.

While some may feel like sporting a luxury watch or designer clothes will draw people toward them, it actually does the opposite, making you a less attractive potential friend, according to a trio of researchers from Michigan, Singapore, and Israel. Over the course of six different experiments, the researchers found that study participants tended to think that high-status markers like fancy cars would help them make new friends. The trend stayed true across both participants recruited using Amazon Mechanical Turk and upscale shoppers stopped for a survey in a high-income suburb.

People thought that showing up to an outdoor wedding in a luxury car or going out to a downtown bar wearing a fancy brand-name watch would lead people to be more attracted to them as potential friends, compared to someone driving a basic car or wearing a generic watch. Yet participants also rated themselves as being more willing to befriend someone with generic clothes and cars than someone who flashed designer goods.

The paradox makes a little more sense if you go back to the idea of “keeping up” with our neighbors. People want to look high status in comparison to others. They don’t want to hang out with people who are flashing around luxury goods—they want to be the flashier ones.

[h/t The Outline]

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