Tuesday, November 23, 2021

Hope for Critically Endangered Condors through Parthenogenesis

For the critically endangered California condor, a recent discovery of a "virgin birth" may provide a new hope for the survival of their species. This incredible phenomenon was not witnessed, but rather discovered through regular genetic testing of captive birds. While the conservation geneticists at the San Diego Zoo Wildlife Alliance were conducting a genotypic survey, researchers discovered that two male chicks, hatched in both 2001 and 2009, were related to their mothers but did not contain any DNA from a father. This indicated that the California condor is capable of parthenogenesis, or reproduction from an ovum without fertilization. Their findings were unique not only because the chicks were fatherless, but also because the females did have access to a mate-- a first for any avian species.  The results of the study showed that the eggshell membranes of each bird had the male ZZ sex chromosomes, but "all markers were only inherited from their [mothers]." A total of 467 male condors within a breeding pool were tested to confirm this. 

This is an incredible find for researchers as they race to save the species from extinction. And while the parthonates (or offspring of the mothers) have since passed, this discovery may help biologists for decades to come. The California condor's numbers had dipped down to only 23 individuals by 1982 and all remaining individuals were placed into a captive breeding program by 1987. Since captive-bred condors were first reintroduced in 1992, their numbers have grown to 500. This is still far off from being a healthy population, but advancements in  research will help ensure the remaining birds continue to be genetically diverse and healthy 

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