Genetic Compatibility

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Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and seniors. Students have the unique opportunity to meet professionals working for the San Diego Zoo, Safari Park, and Institute for Conservation Research, learn about their jobs and then blog about their experience online. Follow their adventures here on the Zoo’s website!

jade_W3_pic2What makes the perfect partner? Well, evolutionarily speaking, it is the one that can produce the most viable offspring. Everyone who has taken a biology class has heard the term “survival of the fittest,” but how does an animal know which mate will produce the most fit offspring? Of course there are many telling signs, such as healthy plumage, long antlers, or vibrant coloration – but there is an even more exact method. This is where Steven Thomas comes in, a Senior Research Technician in the Genetics Division of the San Diego Zoo Institute for Conservation Research (Institute). Mr. Thomas’s purpose of working with California condor DNA is to increase the number of viable condors so that the species is not lost forever.

Before coming to work at the Institute, Mr. Thomas began his journey in genetics at San Diego State University as a biology major. Mr. Thomas talked with great respect for his alma mater, especially its biology program. After finishing his undergraduate degree, Mr. Thomas went on to complete his masters in evolutionary biology. All of this schooling prepared him to work in a lab. One job in particular that Mr. Thomas loved was working in a spider lab, extracting and analyzing their DNA. Mr. Thomas also worked at the Salk Institute for Biological Studies for a year, where he worked on protein biology related to drug addiction. Mr. Thomas’s education and experience most certainly helped him land his most current position at the Institute.

Now you might be asking yourself, “What exactly does a Senior Research Technician in the Genetics Division do?” A large part of Mr. Thomas’s job is analyzing the DNA of California condors to verify parentage. A typical day for Mr. Thomas begins by extracting DNA. The DNA samples that he works with come from a variety of sources, such as blood, feathers, or even a condor eggshell membrane. One method Mr. Thomas uses requires a phenol-chloroform extraction step to obtain the DNA, a process that must be contained inside a fume hood because of its toxicity. Now that he has the DNA he can begin analyzing it. In order to tell individual condors apart, Mr. Thomas examines markers on the DNA through a process called microsatellite analysis. In microsatellite analysis, DNA is amplified by PCR (polymerase chain reaction) so that the markers on the DNA can by inspected. Amplifying one marker at a time wouldn’t be efficient, so Mr. Thomas uses a multiplex PCR to enlarge multiple markers at once. Although studying the markers is a critical step, the process of DNA analysis is not over yet. Next, Mr. Thomas utilizes a genetic analyzer, a machine that determines the sequence of nucleotide bases on a segment of condor DNA. When DNA is run through the genetic analyzer, the different nucleotide bases are differentiated with various colors, making it easy to compare the nucleotide sequences. Once Mr. Thomas has completed these steps, he has all the pieces to the condor DNA puzzle. Now Mr. Thomas is able to run a parentage analysis to determine which condor chick belongs to which two condors. This information is very useful as it helps in identifying which condors create viable offspring.

All of this information may cause you to question what the point of this process is, after all, up until recently, animals haven’t had the luxury of running their DNA through a genetic analyzer. Even though this method of breeding condors may seem unnatural, it is actually helping the California condor population stay strong and viable. California condors have been through a severe bottleneck, which caused a drastic drop in population numbers and genetic diversity. Matching condors based on genetic compatibility has helped the California condor population grow and flourish. Also, keeping accurate records of ancestry is very important. In this way, Mr. Thomas has been able to help in the recovery of this magnificent species.

Jade, Career Team
Week Three, Winter Session 2013