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A NYtimes article published today discusses DNA testing as a "family history research tool."

Among the famous whose DNA has been tested is Marie Antoinette, who belonged to maternal Haplogroup H (along with about half of all Europeans).

Katie Couric (maternal Haplogroup K) is genetically linked to a 5,000-year-old iceman whose body was recently discovered in the Alps. And Jesse James? T2, a subgroup of maternal Haplogroup T.

Whether you've mapped your family's taproots or would rather forget them, you've probably had to at least consider those who came before those who came before you—for scholarships, or medical histories, or perhaps to rationalize some quirk or talent. I have to say I've never been that interested in the fame or foibles of my own genetic line backwards; maybe I'm a hopeless solipsist, maybe I'm banking on reincarnation; my lazy historical eye aside, there are a few notables who'd stand out whether I was wrought from their blood or not. Namely, my saloon-operating great-great grandmother who partied & patrolled in Buffalo, NY. And I'd love to be able to regale you with gypsy rock stars who flanked the Vltava River on my mother's side, but the results aren't in yet, so I'm going to hand this one over to you: who is the most fascinating, mysterious, or just plain irreverent person occupying a box seat in your family tree? Or: would you (or have you) shed some blood to find out more about your ancestry?

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science
Scientists Figure Out Why Roses Don't Smell as Good as They Used To
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Roses are red, violets are blue, but they just don't smell like they used to.

A team of 40 international researchers has successfully mapped an heirloom rose's genome and learned where the bud's color and scent come from—and how to tweak those traits to yield a more fragrant flower. Historically, rose breeders have opted for pretty petals over pleasant perfumes, and as a result, the rose's natural scent has faded over time, according to Science News.

The study, published in the journal Nature Genetics, reports that some of the genes of the "Old Blush" pink China rose cancel each other out, "with some turning on to brew a scent component while others shut down manufacture of anthocyanin pigments needed for rosy petals," Science News reports. The researchers also found 22 new biochemical steps in the production of terpenes, the volatile organic compounds key to the rose's perfume. With a better understanding of the complex relationship between color and scent, breeders of both roses and other plants could start producing flowers without sacrificing one trait for the other.

"The big challenge is you need to know what to edit," Todd Mockler, a plant researcher who was not involved with the rose study, tells The New York Times. “You can't just randomly start editing. You have to know what to target. The only way to know that is to have a genome sequence.”

The rose is most closely related to the strawberry plant, but it also has family ties with the apple and pear. Given that modern roses contain a blend of genes from between eight and 20 different species, mapping its genome was no small feat. It took researchers eight years to complete this study, according to the BBC. And while it's not the first time the rose genome has been mapped, this new analysis is far more comprehensive.

Similarly, the sunflower contains a complex genetic code, but scientists were able to map its genome last year, serving to aid future researchers and flower breeders. 

[h/t BBC]

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Big Questions
How Do Eyes Get Their Color?
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Paul Newman wasn't too fond of his blue eyes. The actor, who earned admiration from audiences and critics in everything from Cool Hand Luke to The Verdict, had a piercing set of blue irises that were as recognizable as Sylvester Stallone’s deltoids. He found the attention they received slightly grating. “If blue eyes are what it’s all about … I may as well turn in my union card right now and go into gardening,” the actor/philanthropist told The Saturday Evening Post in 1968.

If Newman knew the science behind his distinctive peepers, maybe he wouldn’t have been so hard on them. Although your genes are responsible for the color of your eyes, it’s a very complicated hereditary trait. Where you fall on the spectrum from light Newman blue to dark brown is the result of how much melanin pigmentation you have.

The iris—the colored part of the eye surrounding the pupil—is made of layers. The iris pigment epithelium is in the back and has some black or brown pigmentation to it. The layer over it is the stroma, which sometimes has brown melanin pigment, as well as colorless collagen. The black dots or “strings” you see in the eye are typically coming from the epithelium and are visible through the stroma.

Color is determined by the amount of melanin in the stroma. If you have brown eyes, you have brown melanin in the stroma that will absorb available light and make the iris appear darker in color. If you have green eyes, there’s not much melanin or collagen, and the light will be scattered. If your eyes are blue, you have no melanin at all—all of the light hitting the eye is scattered and reflected back. That’s why people with blue or green eyes can seem to shift eye color, depending on the amount of light in a room.

So how are genes involved? While they don’t directly program your body for a certain eye color, they do affect the quality and quantity of melanin in the stroma, which dictates your hue. While Newman’s brand of blue is a little more unusual than brown—the most common color—he probably would’ve been equally perturbed by grey. That shade, possibly caused by excess collagen, is considered the rarest eye color of all.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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