Nov 02, 2021 19:00:00

It turns out that the endangered California condor was born from an 'unfertilized egg'

By

Stacy Spensley

The California condor , which lives in the western United States, is considered to be endangered by the International Union for Conservation of Nature due to its small population. A research team at the San Diego Zoo , which has a breeding program for California condors, has revealed that California condors were born from unfertilized eggs .

Facultative Parthenogenesis in California Condors | Journal of Heredity | Oxford Academic
https://academic.oup.com/jhered/advance-article/doi/10.1093/jhered/esab052/6412509

San Diego Zoo Wildlife Alliance Conservation Scientists Report First Confirmed Hatchings of Two California Condor Chicks from Unfertilized Eggs – San Diego Zoo Wildlife Alliance Stories
https://stories.sandiegozoo.org/2021/10/28/san-diego-zoo-wildlife-alliance-conservation-scientists-report-first-confirmed-hatchings-of-two-california-condor-chicks-from-unfertilized-eggs/

California condominiums can have 'virgin births,' study finds
https://www.nbcnews.com/science/science-news/california-condors-can-virgin-births-study-finds-rcna4087

The San Diego Zoo Wildlife Alliance, which operates the San Diego Zoo, has been collecting genetic information from 911 California condors over the past 30 years in order to ensure genetic diversity in California condors. In the process of analyzing the genetic information, it was discovered that two California condors only had 'mother's genes.'

The San Diego Zoo Wildlife Alliance research team searched genetic databases for individuals with suitable genes to be the father, but were unable to find any. This led the team to conclude that the two California condors had no biological father.

According to the research team, examples of parthenogenesis in birds

are rarely observed in 'female birds that cannot come into contact with males.' However, the mothers of the parthenogenetic individuals discovered this time lived with the males, and one gave birth to 11 chicks and the other to 23 chicks through sexual reproduction. In addition, the latter mother gave birth to two chicks through sexual reproduction after the parthenogenetic individuals gave birth. Based on this, the research team stated, 'This is the first discovery of a parthenogenetic individual in the California condor, and the first discovery of a bird that engages in normal sexual reproduction with males,' emphasizing its importance.

Some California condors live for about 60 years, but one of the two parthenogenetic individuals died at the age of 2 in 2003, and the other died at the age of 8 in 2017. The research team also claims that no parthenogenetic individuals have been searched for using molecular genetic techniques before. 'This discovery suggests that parthenogenesis may have actually occurred in other species, but has not been detected,' said Oliver Ryder, a member of the research team.

Although parthenogenesis is rare in birds, many reptiles and fish species are known to reproduce by parthenogenesis. In 2017, a female shark was reported to have changed its reproductive strategy from sexual reproduction to parthenogenesis after being separated from the male.

Cases observed in which sharks separated from males spawned alone and quickly changed their reproductive strategy from sexual to asexual reproduction - GIGAZINE