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How To: Change Your Child's DNA

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When Willie Nelson admonished mamas everywhere to not let their babies grow up to be cowboys, he had no idea how accurate his assessment of a mother's power really was. Turns out, moms have a lot of control over what their babies become, both before and after birth.

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To be a mom (sorry, guys)

Using Your Dinner
For instance, research done at Duke University Medical Center in 2003 revealed that what a mother eats before and during pregnancy can actually switch certain genes on and off in her child. The study took a group of obese, yellow mice and fed them diets that were rich in the nutrients vitamin B12, folic acid, betaine and choline. Despite still carrying their mother's genes for yellow fur and obesity, the baby mice born from this test were brown and remained svelte throughout their lives. This works because the gene that controls both coat color and appetite is affected by a chemical molecule called methyl groups, of which vitamin B12, folic acid, betaine, and choline are chock full. Methyl groups can switch genes on or off or, in some cases, just increase or decrease their impact.

epimice.jpgUnfortunately, while this might be a great thing sometimes, like say if it cut out the gene that might give your kid diabetes or schizophrenia, methyl groups might also turn off "good" genes, like ones that inhibit tumor growth. Right now, nobody really has a good enough idea of how methyl groups work to know how to target in on specific "bad" genes without impacting good ones. We do, however, have plenty of evidence that what pregnant moms eat affects gene expression and can have surprising consequences a long way into their children's lives. For instance, according to an October 2003 New York Times article on the subject, famines that struck Holland after World War II left many fetuses (and their mothers) malnourished. Years later, Holland saw a big increase in the number of adults with schizophrenia, an increase directly linked to what nutrients those adults had (or, rather, hadn't) gotten in the womb.

Using Your Love
Just because you've exited the womb doesn't mean your mother stops having power over your DNA expression. Research done by neurobiologists at Columbia University and Canada's McGill University has shown that maternal behavior after birth can also lead to a child's genes being turned on and off—in this case, genes that will eventually determine how that child parents their own offspring. According to a May 2006 Discover magazine article, neurobiologists studied two groups of rats, those that spent a lot of time grooming and licking their babies and those that didn't. It turned out that, if a female baby rat didn't get licked enough then her body turned off a series of genes that should have produced certain "mothering" and "love" hormones, like estrogen and oxytocin. Deprived of those, the female rat grew up to exhibit the exact same insufficiently nurturing behavior her mother had shown her—thus continuing on the cycle for another generation. On the other hand, when a baby girl rat got an extraordinary amount of lick-based attention from her mommy, she went on to actually have higher-than-average levels of estrogen and oxytocin. Again, the expression of genes and the production of hormones caused her to display maternal behaviors that were similar to her own mother's.

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science
Geological Map Shows the Massive Reservoir Bubbling Beneath Old Faithful
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Yellowstone National Park is home to rivers, waterfalls, and hot springs, but Old Faithful is easily its most iconic landmark. Every 45 to 125 minutes, visitors gather around the geyser to watch it shoot streams of water reaching up to 100 feet in the air. The punctual show is one of nature’s greatest spectacles, but new research from scientists at the University of Utah suggests that what’s going on at the geyser’s surface is just the tip of the iceberg.

The study, published in the journal Geophysical Research Letters, features a map of the geological plumbing system beneath Old Faithful. Geologists have long known that the eruptions are caused by water heated by volcanic rocks beneath the ground reaching the boiling point and bubbling upwards through cracks in the earth. But the place where this water simmers between appearances has remained mysterious to scientists until now.

Using 133 seismometers scattered around Old Faithful and the surrounding area, the researchers were able to record the tiny tremors caused by pressure build-up in the hydrothermal reservoir. Two weeks of gathering data helped them determine just how large the well is. The team found that the web of cracks and fissures beneath Old Faithful is roughly 650 feet in diameter and capable of holding more than 79 million gallons of water. When the geyser erupts, it releases just 8000 gallons. You can get an idea of how the reservoir fits into the surrounding geology from the diagram below.

Geological map of geyser.
Sin-Mei Wu, University of Utah

After making the surprising discovery, the study authors plan to return to the area when park roads close for the winter to conduct further research. Next time, they hope to get even more detailed images of the volatile geology beneath this popular part of Yellowstone.

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Animals
Why Do Female Spotted Hyenas Give Birth Through Their Pseudo-Penises?
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At the zoo, you can sometimes tell the difference between male and female animals by noting their physical size, their behavior, and yes, their nether regions. Hyenas, however, flip the script: Not only are lady spotted hyenas bigger and meaner than their male counterparts, ruling the pack with an iron paw, they also sport what appear to be penises—shaft, scrotum, and all.

"Appear" is the key word here: These 7-inch-long phalluses don't produce sperm, so they're technically really long clitorises in disguise. But why do female hyenas have them? And do they actually have to (gulp) give birth through them? Wouldn't that hurt … a lot?

The short answers to these questions are, respectively, "We don't know," "Yes," and "OW." Longer answers can be found in this MinuteEarth video, which provides the full lowdown on hyena sex. Don't say we didn't warn you.

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