In the decades since they began to make their Marvel Comics debut, the X-Men have sparked quite a lot of questions amongst fans. If you're among those who have been wondering one specific thing - "Why are certain mutants blue?" - your answer may have arrived. A new article on The Science Of breaks down the science of the X-Men's blue mutants, such as Mystique, Nightcrawler, Apocalypse, and Beast. Dr. Eric Spana, a biology professor at Duke University, revealed how the X-Men's various genetic makeups could have resulted in blue skin, based off of examples in the animal kingdom.
"For the X-Men, two of the above examples could actually explain how they get blue – humans don't make chitin, so that's out," Spana says. "The keratin protein is not only a major protein component of feathers, but also human hair – and nails, etc. So might Beast's blue fur derive from two different mutations: one that causes long fur/hair and another that organizes the keratin in the hair to reflect blue light like a blue jay? Nightcrawler, however, doesn't have that excess hair, but has blue skin. His mutation might be one like the ordered collagen fibers seen on the noses and backsides of mandrills and give him blue skin all over."
Spana also cited some real-life science behind blue skin, which would theoretically throw a wrench in the possibility of a healthy human mutant naturally having that pigment.
"We can sum up color into two broad categories: Structural color and pigment color," Spana revealed. "Pigment color is what makes your jeans, pen ink and stained-glass blue. Structural color is a physics effect of light absorption and reflection where only the blue light is reflected and seen by your eyes. There are only a few organisms on Earth that can make a blue pigment – a few butterfly species, for example, and there are no vertebrates."
Of course, there are some outlying examples of humans with blue-tinted skin, most notably in the Fugate family from the late 1800s and early 1990s. As the report outlines, several members of that family suffered from methemoglobinemia, a recessive genetic trait that prevents the blood from carrying or providing the necessary amount of oxygen.
"In severe cases of this condition, altered oxygen binding to that form of hemoglobin causes lowered oxygen availability and cyanosis which is a bluish skin trait," Spana explained. "This seems unlikely for X-Men as the low oxygen causes substantial health problems, not superhero traits."
What do you think of the science behind why some X-Men could be blue? Share your thoughts with us in the comments below!