Parentage Testing for California Condors
Paternity tests for humans, using special DNA markers known as microsatellites, have become commonplace, and it takes only a cheek swab, a few plucked hairs, or a small amount of blood to provide a human genetics lab enough starting material to either confirm or refute alleged parentage. As part of our genetics work to assist in recovery efforts for the endangered California condor, we need only a large drop of blood, a plucked feather, or a small piece of eggshell membrane to extract sufficient DNA for parentage verification.
So what part has the Institute’s genetics lab played in the long-time recovery program for the condor, and what is involved in parentage determination for this bird?
Over the years our ability to use genetic techniques for species identification, relatedness studies, sexing, and parentage verification has provided a great opportunity for fruitful collaborations between field biologists, zoological management experts and the scientists here at the Institute. This has never been more apparent then with the over 30 years of work by Zoo geneticists to help California condor efforts, including assisting Curator of Birds Michael Mace in maintaining the most accurate studbook possible by determining the sex of all condor chicks, as well as confirming parentage.
Our efforts to genetically identify a chick’s parents initially focused on just those birds hatched from eggs laid in the wild, and we were able to resolve parentage and answer questions that arose due to field observations. However, a couple unexpected discoveries led us to start examining parentage for all California condors, and we came to realize that occasionally the findings for these birds can be as surprising as when certain daytime talk show hosts spring unanticipated paternity results on often flabbergasted guests!
With the help of past and present Genetics staff members, almost 700 of the 806 birds in the 2016 condor studbook have had their parentage checked. The procedure includes amplifying a condor’s DNA using 22 different condor-specific genetic markers or loci in a process known as PCR. The resulting fluorescent-labeled PCR products are run in a laser-based piece of equipment known as a genetic analyzer, and the data are analyzed with the help of a software program. At each locus, a chick inherits one form of a gene or allele from dad and one allele from mom, and by examining all 22 loci, we can either exclude or confirm a particular condor as a parent, with only very low odds that any bird qualified as a parent just by chance alone.
The good news is that almost 99% of the California condors we studied were confirmed to their studbook parents. The not bad but rather interesting news is that we resolved a couple cases of possible misidentification, established the actual parents for two chicks, each attended by a trio of adults in the wild, and, discovered that a male condor flew miles away from his northern California coastal home, mated with an inland female, and then left without anyone the wiser until he unexpectedly qualified as sire of her chick!