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Scientists Say Chronic Pain Can Alter DNA

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Pain hurts. But when that pain is ongoing, it does more than just hurt the affected body parts. Chronic pain can make it hard to think or function and can lead to depression and strained relationships. Now researchers have found evidence that prolonged exposure to pain can even alter DNA in the brain and immune system. They published their findings last week in the journal Scientific Reports.

The National Institute of Neurological Disorders and Stroke estimates that more than 100 million Americans live with chronic pain. But despite its prevalence and devastating consequences, chronic pain is still not very well understood.

The authors of the latest study wondered if the effects of prolonged pain could reach the genetic level. They examined DNA from the brains and white blood cells of both healthy rats and rats recovering from nerve injuries. The researchers focused on tracking the chemicals called methyl groups, which are considered a good indicator of changes in gene expression.

They expected to find at least a few altered genes in the DNA of the pain group. They found a whole lot more than that. "We were surprised by the sheer number of genes that were marked by the chronic pain—hundreds to thousands of different genes were changed," study co-author Moshe Szyf said in a press statement.

Many of those genes were in areas of the brain associated with cognitive issues, depression, and anxiety. "We found that chronic pain changes the way DNA is marked not only in the brain but also in T cells, a type of white blood cell essential for immunity," Szyf continued in the press statement. "Our findings highlight the devastating impact of chronic pain on other important parts of the body such as the immune system. We can now consider the implications that chronic pain might have on other systems in the body that we don't normally associate with pain."

As Szyf and his colleagues emphasize in their paper, these findings have "very broad implications." Still, it’s important to keep in mind that these experiments were performed on rats, not humans. Further studies will be needed to confirm these results and explore their relationship to the human experience of pain.

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Food
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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