Embryonic Endeavors

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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!

There are always new areas of study emerging in the field of science, and today we received an in-depth look at reproductive physiology with Institute Scientist, Dr. Thomas Jensen. Although not the newest addition to the different areas of science, the scientists who study reproductive physiology are making a lot of firsts in the field, several accomplished by our presenter, Dr. Jensen.

Dr. Jensen started out at the Zoo as a Postdoctoral Research Fellow. First, he went through Northern Arizona University’s undergraduate program to receive a degree in Zoology and the University of Notre Dame’s graduate program for a degree in Avian Phisiology. Back when Dr. Jensen was in high school, he read an article about how a few scientists in Florida had frozen the cells of a certain type of sparrow that had gone extinct in the area. This process of freezing cells, or cryopreservation, allows scientists to possibly regenerate the animal that the cells came from. This article helped inspire Dr. Jensen’s passion for birds and his pursuit to help them. Throughout his many years working in avian research, Dr. Jensen worked alongside many experts in the field, eventually securing a position at the San Diego Zoo Institute for Conservation Research where he has worked in the Reproductive Physiology Division for the past thirteen years.

Dr. Jensen works on several projects, and one of his most recent ones enabled him to work with kiwis. Dr. Jensen, along with his associates, studies some of the DNA and chemicals, known as fecal steroid metabolites, found in the feces or poop of kiwis. The results can be used to estimate where the bird is in its reproductive cycle, find out which bird it is, who it is related to, as well as what it eats. Dr. Jensen also performs ultrasounds on kiwi eggs to see how the chicks are growing. Dr. Jensen was actually the first, and currently one of only two people, who know how and have performed this procedure. He has also been able to observe kiwi behavior at the San Diego Zoo and develop techniques with them that can be applied to kiwis in their native habitats. It is helpful to create techniques that allow scientists like Dr. Jensen to take fecal samples or perform an ultrasound with the kiwis in the Zoo’s managed care, because the kiwis are not as bothered by human presence. The kiwis at the Zoo don’t get as stressed or anxious as wild kiwis would, and the less stress wild kiwis experience, the easier it is for them to work with their mate to produce offspring.

Another major aspect of Dr. Jensen’s work is to sex birds. This simply means that he takes a DNA sample from a bird’s egg and tests it to find out the gender of the chick. This process requires a steady hand and does not hurt the embryo in any way. When Dr. Jensen hosts seminars at the Institute and works with the Institute’s fellows (interns), he teaches them this procedure. First, he sands a hole on the egg that does not break the shell, then, with the use of a microscope and forceps, a tool that looks like tweezers, he peels the thin eggshell membrane away, so the embryo can be accessed. At this stage, if the embryo is old enough, you can see the heartbeat. Finally, he uses a pipette to take a sample of blood that can then be sent to be analyzed. After the sample is taken, vet tape is put over the opening in the egg, and it is as good as new. Although this process is used on tons of different bird species, it was particularly useful for the Storm’s stork. There was an instance not too long ago when the Storm’s storks were only laying eggs that were male and they needed to have some females so they could make breeding pairs, which is rather hard when you have only one gender. To fix the problem, eggs were sent over to Dr. Jensen and he would go through the procedure and find out whether the chick was  male or female. If it turned out to be a female, they would keep the egg. If it were a male, they would send it to another zoo. Thanks to the help of this sexing technique, there are now four female Storm’s storks at the Zoo ready to be paired for breeding.

Just like any other career, to be able to work as a scientist in the field of reproductive physiology like Dr. Jensen, familiarity with the subject is definitely required. There are several internships or fellowships available at the Zoo, the Safari Park, and the Institute. In these programs, college students are able to participate and conduct research on projects with professionals like Dr. Jensen and his kiwi project. Opportunities like that,  provide students with not only knowledge and experience, but also a foot in the door to work on other projects with some of the scientists they meet. For more information, visit http://www.sandiegozoo.org/volunteer/ and find the internship that’s right for you.

Madison, Careers Team
Fall 2012, week six