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SciShow News shares the latest science headlines, including a newly-found butterfly that’s half male and half female, and new insights into the association between cancer and … breathing.

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 Dual-sex butterfly

Last week we told you about how monarch butterflies are disappearing because of industrialized agriculture and massive use of herbicides, making their habitat less exist-y. But this week, another butterfly's making headlines for a very different reason.
A volunteer for the Natural History Museum at Britain's Drexel University was working in a live-butterfly exhibit when he discovered a brush-footed butterfly that was half male and half female. Its two left wings were black and blue and green, which is indicative of a male, while the two right wings were brown with yellow and white spots, indicative of a female. The right wings were also larger than the left wings, and even the coloration of its head and thorax and abdomen was split in two.
The volunteer took the odd-looking brush-foot to the museum's lepidopterist – that's what they call butterfly scientists – and he diagnosed it with a condition called bilateral gynandromorphism. Gynandromorphs are created when there's an error in the division of sex chromosomes during the earliest stages of embryonic development. As the very first cells that develop in the insect begin to divide, one cell gets a male chromosome while the other gets female chromosomes. All the subsequent divisions from the male cell are then male, and all the new cells copied from the female cell are female. This keeps going until you end up with an animal that looks like a male on one side and a female on the other.
This condition is extremely rare, and no, it can't happen in people, but we did do an entire episode on the biology of gynandromorphism, which is right here!


Also in the news this week: some new insights into one of our oldest friends, who might turn out to be doing us wrong: oxygen. If you've ever taken a trip from sea level to a place up in the mountains, you may have found yourself short of breath when you got there, huffin' and puffin' and gaspin' for air. That's because at low elevations, atmospheric pressure is higher, which means oxygen  molecules in the air are compressed closer together by the weight of the air above them. But at higher elevations, the pressure is lower, and those oxygen molecules are fewer and farther between.
As a result, a person at sea level will inhale 40% more oxygen than someone at 3000 meters. And now, according to a new study out this week, all that extra oxygen that we inhale at lower elevations might increase our risks for some kinds of cancer.
Researchers from the University of Pennsylvania and the University of California, San Francisco, discovered a correlation – and that's important – between elevation and lung cancer rates in the Western United States. The scientists examined four years' worth of cancer incidents data from 260 counties in states where the elevation gains exceed 3,000 meters. After crunching the numbers and adjusting for a wealth of risk factors like age, ethnicity and smoking, the scientists found that lung cancer rates dropped by an average of 12.7% for every 1 km of elevation rise. Other cancer rates like those of the breast and colon were unaffected by the change in altitude, leading researchers to theorize that breathing in more oxygen might increase the risk of respiratory cancers. Now wait, hear me out, because this might not be as crazy as it sounds. When our cells metabolize oxygen they create as a by-product oxygen atoms that have one or more unpaired electrons, making them highly reactive. These are called reactive oxygen species and they include free radicals which you might have heard of. When compounds in your body react with these oxygen atoms, they get oxidized, having their electrons stolen from them faster than I can steal the last doughnut. So an abundance of reactive oxygen in your body can damage your body’s cells – even your DNA – which can lead to the development of cancer. Previous studies have suggested that a lot of this oxidizing damage takes place in the lungs specifically, and one recent study showed that reducing ambient oxygen by 50% could actually shrink tumours in mice.
But before you pack your bags and head to the mountains, remember this study does not say that breathing at sea level causes cancer. It only shows that they have found an association between elevation and lung cancer rates. I mean, people have been living at sea level for a long time and they have lived to tell about it. At least for, you know, the normal amount of time. Also, don’t stop breathing, that would be a faster way to die, than, yeah.

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