

“I think it's one of the most important studies in the field of parthenogenesis and birds in a long time,” says Warren Booth, an evolutionary biologist at the University of Tulsa who studies facultative parthenogenesis in snakes and was not involved in this paper. Neither bird was particularly robust, but the fact that they survived beyond hatching is a big deal. They were also entirely homozygous: Instead of having a mix of dominant and recessive genes, all of their alleles were exactly the same. In fact, they didn’t have DNA from any registered male condors.

These two chicks, which had hatched about a decade apart in the early 2000s, had DNA that matched their mothers’ DNA, but they didn’t have a single gene from the male condors that were listed as their fathers. There are now about 500 condors in California and Mexico, but the bird is still critically endangered, so scientists carefully track the parents and chicks in the zoo’s breeding program.Ĭhemnick had been double-checking the parentage of each chick that had hatched since the program began, using DNA obtained from blood samples. In 1987 conservationists captured the last 22 birds from the wild and slowly nursed the population back from the brink of extinction. The zoo is home to dozens of California condors, part of a rehabilitation effort that began after the birds’ population plummeted during the 20th century. They were standing outside the San Diego Zoo Wildlife Alliance at the end of a work day in 2013, and Chemnick, a researcher in the alliance’s conservation genetics lab, was describing a puzzling situation. Oliver Ryder and Leona Chemnick’s big “Aha!” arrived in a parking lot. Archimedes had his famous “Eureka!” moment about water displacement after stepping into a very full bath.
