( Click here to see an image of the rainbow chick
As excitement reaches a fever pitch with news of the parents of California condors bringing two newborn chicks to life after a failed attempt at fertilization, there’s now even more to celebrate for the birds’ newfound five-day-old relatives.
“Some of the condor chicks are being assessed as possible genetic mixers in an attempt to manage genetics within the population,” Jay Gall, vice president of the California condor conservation program at the Peregrine Fund in Bakersfield, California, said in a phone interview. “They are doing this to look for genetic diversity that could reduce problems of fragmentation in breeding,” he said.
Like male condors, the new hatchlings also have a number of genetic markers associated with multicellular, hard-to-reproduce hybrids, Gall explained.
Condors are the largest land animals on Earth and iconic of California. Those that pass a group pass, through their reproductive cycles, to raise pups that mate and have sex in the nest.
Scientists started raising the possibility of the gender being swapped out with a process called hybridization in the 1990s, or when females start laying eggs in the males’ territories and vice versa. Attempts were made to egg protect the new embryos against fragmentation that could lead to a female pup with the wrong sex.
Dahlia Guzman of the Peregrine Fund explained the switch is dependent on sperm to mate with the female and in vitro fertilization of eggs. For tests, semen is taken from the parents, after which each parent and pup is tested for chromosomal anomaly that might affect a hybrid offspring.
“Males laid eggs during sex, while females laid eggs in pens,” Gall said. “The parent claims the egg and there’s a cell transfer between egg and sperm until it’s ready to implant into the uterus. About 15 percent of eggs that are deposited actually grow and hatch, so if the cells become heterozygous, the parent claims the egg and you have a sterile or hybrids or a high proportion of no pregnancy in pairs that are trying to retain.
“Some may have been more successful in mating than others,” he added.
Although the rarity of the females’ eggs and their own old reproductive cycles created a disadvantage for hybridization, they eventually developed a way around it.
“They were able to bring a couple of eggs to incubation and have the cells ‘spliced,’ and then incubate them and give the next batch of eggs to the next chick and the process went forward,” Gall said.
The girls did not bear any males, Gall said. The babies hatched in separate nests and did not cross back as this could complicate efforts to determine them as twins. The California condor can survive with just one egg in a nest, with a father and a mother incubating it.