Preserving the Exotics

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Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and senior. 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 many endangered species in the wild today. Some are endangered due to habitat loss or human conflict, while others might have trouble reproducing. On the issue of reproduction, Dr. Tom Jensen helps combat the problem using a variety of sophisticated methods including: the use of stem cells, somatic cell nuclear transfer, and embryo sexing.

With the use of stem cells, scientists like Dr. Jensen, are able to preserve both exotic and captive species. Germ stem cells are very useful because instead of bringing the endangered species to the research lab (which involves obtaining permits to allow for travel), the cells can be taken in the field and be brought to the lab, which is much easier than bringing the whole animal in. Once in the lab, a process called somatic cell nuclear transfer is used with the stem cells taken from the endangered species. Using an electric current, this process binds the stem cells to the reproductive cells of a surrogate. This allows species in captivity to carry the genetic material of wild endangered species. This surrogate carrying the endangered stem cells can now mate with a female of the donor species in a captive setting, and the offspring will be the same species as the exotic donor.

Another process used in the lab is embryo sexing. For birds, scientists sand off part of the eggshell of a mid-incubation embryo. With the membrane still intact, it is slowly peeled back from the contents of the egg and a 60 micro-meter needle is then inserted into a blood vessel surrounding the embryo to extract germ stem cells. After the procedure is over, the hole is covered with vet tape and the embryo continues developing normally in the incubator. For sex determination, the DNA from the blood is analyzed using Polymerase Chain Reaction (PCR) and electrophoresis to see if the embryo is male or female. This process has been used to help manage a variety of endangered birds in captivity, including the storm’s stork and red crowned crane. This technique allows researchers to determine the sex of the embryo prior to hatching, allowing for better selection of individuals for breeding.

Scientists, like Dr. Jensen, in the field of reproductive physiology, are constantly coming up with ways to help combat the endangerment of different species. Whether in captivity or in the wild, these species are being helped by research done in labs. Species have been benefiting from techniques such as embryo sexing, use of germ stem cells, and somatic cell nuclear transfer, which are still being used today and found to be very effective. For example, the storm’s stork, a critically endangered species, hatched five males at the Safari Park. This is a problem since breeding programs need an appropriate number of males and females to be successful. After using these different in-ovo sexing techniques, four females were allowed to hatch within the next two years.

The research and techniques for embryo sexing, the use of germ stem cells, and somatic cell nuclear transfer have all been very useful in captive breeding programs. They have allowed for controlled hatching leading to a benefiting breeding environment. The lab work done is an important aspect of the captive species and the preservation of exotic animals in the wild.

Hayden, Conservation Team
Fall 2012, Week 6