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Scientists Identify the Genes Associated With Gray Hair and Unibrows

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For the first time, scientists have identified the gene that makes your hair go gray. As part of a study published in Nature Communications, they also identified a new set of gene variations associated with features like unibrows, thick facial hair, and curls.

Led by geneticists at University College London, a group of researchers analyzed the genomes of more than 6300 Latin Americans (54 percent female, 46 percent male) from Brazil, Colombia, Chile, México and Peru to find the genes associated with the features of both scalp and facial hair. They looked for associations between certain genetic features and traits like hair color, propensity toward graying or balding, beard thickness, eyebrow bushiness, and unibrows. The blood samples used in the study came from a diverse population with mixed European, Native American, and African ancestries.

The gene linked to graying, IRF4, helps regulate and store melanin (the pigment that also determines skin color). Other genes studied included a variant of the FOXL2 gene that seems to be associated with brow thickness, and PAX3, the gene that dictates whether or not you have a unibrow—at least in men. (While both men and women were tested for genetic associations with scalp hair, only men were tested for facial hair characteristics.) 

By finding the genes associated with hair features, scientists may be able to develop ways to change your hair without curling irons, dyes, and cosmetic products. Though it’s a long way away, there could one day be a drug for straightening your hair, to halt your graying at that perfect salt-and-pepper color, or to remove your unibrow. It could also illuminate the mechanisms behind diseases associated with baldness. But really—get working on that anti-unibrow drug, science.  

[h/t Scientific American]

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Researchers Pinpoint the Genes Behind the Durian's Foul Stench
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Durian is a popular fruit in parts of southeast Asia. It's also known for having the most putrid, off-putting odor of any item sold in the produce section. Even fans of durian know why the fruit gets a bad rap, but what exactly causes its divisive scent is less obvious. Determined to find the answer, a team of researchers funded by "a group of anonymous durian lovers" mapped the fruit's genome, as reported by the BBC.

The study, published in the journal Nature Genetics [PDF], contains data from the first-ever complete genetic mapping of a durian fruit. It confirms that durian's excess stinkiness comes from sulfur, a chemical element whose scent is often compared to that of rotten eggs.

Analysis of the fruit's chemical makeup has been done in the past, so the idea that sulfur is a major contributor to its signature smell is nothing new. What is new is the identification of the specific class of sulfur-producing genes. These genes pump out sulfur at a "turbocharged" rate, which explains why the stench is powerful enough to have durian banned in some public areas. It may seem like the smell is a defense mechanism to ward off predators, but the study authors write that it's meant to have the opposite effect. According to the paper, "it is possible that linking odor and ripening may provide an evolutionary advantage for durian in facilitating fruit dispersal." In other words, the scent attracts hungry primates that help spread the seeds of ripe durian fruits by consuming them.

The revelation opens the door to genetically modified durian that are tweaked to produce less sulfur and therefore have a milder taste and smell. But such a product would likely inspire outrage from the food's passionate fans. While the flavor profile has been compared to rotten garbage and dead animal meat, it's also been praised for its "overtones of hazelnut, apricot, caramelized banana, and egg custard" by those who appreciate its unique character.

[h/t BBC]

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Why DNA Is So Hard to Visualize
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Picture a strand of DNA and the image you see will likely be similar to the artist’s rendering above. The iconic twisted ladder, or double-helix structure, was first revealed in a photo captured by Rosalind Franklin in the 1950s, but this popular visualization only tells part of the story of DNA. In the video below, It’s Okay to Be Smart explains a more accurate way to imagine the blueprints of life.

Even with sophisticated lab equipment, DNA isn’t easy to study. That’s because a strand of the stuff is just 2 nanometers wide, which is smaller than a wavelength of light. Researchers can use electron microscopes to observe the genetic material or x-rays like Rosalind Franklin did, but even these tools paint a flawed picture. The best method scientists have come up with to visualize DNA as it exists inside our cells is computer modeling.

By rendering a 3D image of a genome on a computer, we can see that DNA isn’t just a bunch of free-floating squiggles. Most of the time the strands sit tightly wound in a well-organized web inside the nucleus. These balls of genes are efficient, packing 2 meters of DNA into a space just 10 millionths of a meter across. So if you ever see a giant sculpture inspired by an elegant double-helix structure, imagine it folded into a space smaller than a shoe box to get closer to the truth.

[h/t It’s Okay to Be Smart]

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