For Release: May 17, 2005
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Peper Long 
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Zoo Scientists Use Quill DNA to Determine Porcupine Sex
In what may be the first genetic determination of its kind, scientists at the National Zoo tested DNA from porcupine quills to establish the gender of the baby prehensile-tailed porcupine born on April 11.
It's a girl.
Porcupine sexual organs are internal—it can take up to six weeks before the gender is known. The DNA test identified this baby porcupine's gender in about a week.
Scientists at the National Zoo have used DNA from the hair and fecal samples of many other species—including maned wolves and elephants—as a noninvasive way to determine gender, identify pathogens, track reproductive health, and study kinship and genetic variability. Working with Zoo veterinarians and animal-care staff, geneticist Dr. Jesús Maldonado recognized similarities between a strand of hair and a porcupine quill, including the root at the base of the strand, where DNA can be found.
"We thought—since it works with hair, why not try to obtain DNA from the quill," Maldonado said.
Maldonado's lab assistant extracted DNA from small tissue samples sliced directly from the quill's follicle. He then amplified a small piece of DNA that can be found on both male and female sex chromosomesbut differs slightly, making it possible to identify the sex of an individual. Genetic researchers at the Zoo have used this method successfully in determining the sex of elephants, kit foxes, maned wolves and other mammals, but never porcupines, and never using DNA extracted from a quill.
Geneticists at the Zoo analyzed the baby porcupine's amplified DNA by comparing it to its parents' DNA.
The results on the computer screen were so clear, I felt like high-fiving everyone, said Andrew Rivara, one of Maldonado's lab assistants. It was definitely female.
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