Mutation in 'junk DNA' behind several deadly cancers
A single typo in the "dark matter" of the genome drives multiple types of cancer.
- Only about 2 percent of the human genome codes for proteins; the rest is called noncoding DNA.
- We used to think this portion of the genome served almost no purpose. Now, however, we have learned that it performs several important biological functions, though much of it is still unknown. This lack of insight is why it's sometimes referred to as the "dark matter" of the human genome.
- In two studies, researchers from Ontario discovered a mutation in this genetic dark matter that changes how gene products are spliced, potentially resulting in several different kinds of cancer.
The human genome contains over 3 billion base pairs, combining together to form at least 20,000 genes. And yet, we tend to focus most of our attentions on just 2 percent of the genome. This is a fairly reasonable thing to do — this two percent is responsible for nearly all of the daily activity in our bodies. It's the portion of the genome made up of what is known as coding DNA, so-called because it codes for proteins. In the body, proteins perform most of the work, like functioning as enzymes, serving as antibodies, or providing structure and support. On the larger scale, they make up the structure of the body's organs and tissues and allow the body to move.
But another 98 percent of the genome doesn't encode for these critical ingredients to life. It's often referred to as noncoding DNA. We used to think this DNA was completely useless, which explains its earlier name, "junk DNA." Now, we know that although it doesn't code for proteins, it can play a crucial role in regulating the various processes of life.
There is, however, still a lot that we do not understand about noncoding DNA, so it is sometimes referred to by a third name: the "dark matter" of the human genome.
A single typo leading to "hundreds of mutant proteins"
In two recent studies, Ontario-based researchers discovered a mutation within this genomic dark matter that was responsible for causing a wide variety of cancers. "By carefully analyzing these regions," said Dr. Lincoln Stein, co-lead to both of the studies, "we have discovered a change in one letter of the DNA code that can drive multiple types of cancer. In turn, we've found a new cancer mechanism that we can target to tackle the disease."
"We've found that with one 'typo' in the DNA code, the resultant cancers have hundreds of mutant proteins that we might be able to target using currently available immunotherapies," added Dr. Michael Taylor, the other study lead.
This typo was located on the U1 gene. This gene does not code for a protein, and thus counts among the genome's noncoding DNA. This is unusual, since nearly every mutation that causes cancer exists in the coding portion of DNA. That's why Stein was skeptical when Taylor brought him data that implicated the U1 mutation in brain cancers. "I didn't believe it for a second that this was a real finding," said Stein. "I thought it was an instrumentation error. But I thought it was interesting enough to try to either confirm or disprove."
But after conducting an analysis of nearly 3,000 other genomes, the researchers discovered that the same mutation was showing up in a wide variety of cancers. While U1 doesn't code for proteins, it does code for the U1 small nuclear RNA (U1 snRNA). This forms part of what's known as the spliceosome. The spliceosome functions as a kind of processing plant for gene products called messenger RNA (mRNA), which carry the genetic blueprints needed to build proteins.
U1 snRNA binds to these products, indicating where they need to be "spliced," or where they carry unnecessary information that should be cut off. However, the mutation these researchers identified changes where U1 snRNA binds to these gene products. In turn, this changes how numerous genes are transcribed, many of which can result in cancer.
While by itself this serves an exciting discovery that may help us identify new ways to treat cancers, it also underscores just how little we really understand about the most fundamental parts of our bodies. In the past, we thought that most noncoding DNA was completely useless. Instead, it was hiding part of the answer to what was the cause of numerous cancers.
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Whether or not women think beards are sexy has to do with "moral disgust"
- A new study found that women perceive men with facial hair to be more attractive as well as physically and socially dominant.
- Women tend to associate more masculine faces with physical strength, social assertiveness, and formidability.
- Women who display higher levels of "moral disgust," or feelings of repugnance toward taboo behaviors, are more likely to prefer hairy faces.
Beards and perceptions of masculinity<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjU5OTg0MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0NzkxMjM3N30.cH-GqNwP5GVqvstgJWAhBPn1B_lYpVEAI0I7iax7EQw/img.jpg?width=1245&coordinates=0%2C1900%2C0%2C849&height=700" id="caae6" class="rm-shortcode" data-rm-shortcode-id="cb0a355a4e8e1899789bc45f3f7aef56" data-rm-shortcode-name="rebelmouse-image" />
Photo Credit: Wikimedia<p>The study used 919 American (mostly white) women ages 18-70 who rated 30 pictures of men they were shown with various stages of facial hair growth. The photographs depicted men with faces that had been digitally altered to look more feminine or more masculine, with a beard and without a beard. The women rated the men according to perceived attractiveness for long-term and short-term relationships. The study found that the more facial hair the men had, the higher the men were rated on their attractiveness, particularly for their suitability for a long-term relationship.</p><p>Part of this might be attributed to facial masculinity — i.e. protruding brow ridge, wide cheekbones, thick jawline, and deeply set narrow eyes — which conveys information to a woman about a man's underlying health and formidability. Women tend to associate more masculine faces with physical strength and social assertiveness. It can also indicate a man with a superior immune response. The researchers suggested that their findings favoring bearded men could be due to the fact that facial hair enhances the masculine facial features on a man's face, like creating the illusion of a thicker jaw line. This could communicate direct benefits to women like resources and protection that would enhance survival among mothers and their infants. In other words, while a beard doesn't mean superior genetics in and of itself, it might be a primitive, ornamental way of saying, "Hey girl, I'm a testosterone-fueled lean, mean, pathogen fighting machine." <br></p><p>It could also be that a beard becomes its own destiny. The researchers in this study cite prior research that found that by growing a beard, men felt more masculine and had higher levels of serum testosterone, which was linked to a higher level of social dominance. They also tended to subscribe to more old-school beliefs about gender roles in their relationships with women as compared to men with clean-shaven faces.<span></span><br></p>
What does disgust have to do with beard preference?<p>Obviously, not all women dig beards. The researchers were particularly interested in what traits make a women prefer bearded men over clean-shaven faces. They looked into several factors including a woman's disgust levels on various concepts, her desire to become pregnant, and her exposure to facial hair in her personal life. </p><p>According to the study, women who were not into facial hair were turned-off by potential parasites or other critters they imagined could be in the hair or skin. Women ranking high on this "ectoparasite disgust" scale might have viewed beards as a sign of poor grooming habits. However, women who ranked higher in levels of "pathogen" did find the bearded men to be desirable, possibly because they perceived beards as a signal of good health and immune function. An intriguing discovery in the study was links to morality. Women who displayed higher levels of "moral disgust," or feelings of repugnance toward taboo behaviors, were more likely to prefer hairy faces. The authors opined that this could reflect a link between beardedness, politically conservative outlooks, and traditional views regarding performances of masculinity in heterosexual relationships.</p>
Additional findings<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMjU5OTg1My9vcmlnaW4uZ2lmIiwiZXhwaXJlc19hdCI6MTYyNDI1NjUyOX0.P9B8WbmJR0q4nfzYZKbuNSA-2SAigVWJgrQE-_Gxlds/img.gif?width=980" id="49143" class="rm-shortcode" data-rm-shortcode-id="2ed3b1d6f20fc170bf2974646e565e8d" data-rm-shortcode-name="rebelmouse-image" />Giphy<p>The correlations that existed between married and single women's rating on the attractiveness of beards were not particularly clear, although the researchers noted that single and married women who wanted children tended to find beards more attractive than the women who didn't want children. They also found that women with bearded husbands found beards to be more attractive, which might indicate that social exposure to beards influences how desirable they are perceived of as being. Or it could be that men with wives who like beards grow beards.</p><p>It's important to note that culture plays a huge role in how attractive women perceive certain male characteristics as being. This study looked at a small, culturally specific group of American women, so no big, universal claims should be made about masculinity, facial hair, and male desirability to women. However, research like this is important in highlighting how human grooming decisions are driven by much more than fashion trends. Sociobiological, economic, and ecological factors all play a part in the way we choose to present ourselves.</p>
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