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!
I bet you’ve heard about genetics and how it’s molding the world that we live in. It’s a field that’s making people look at life in an entirely new way. We had the opportunity to learn about two branches of genetics, cytogenetics and molecular genetics. Geneticists from the San Diego Zoo Institute for Conservation Research explained that both cytogenetics and molecular genetics have made a huge impact on how zoos worldwide function. These researchers use methods that are extremely similar to what is used to test human genetics, solving strikingly similar problems. In fact, the reason researchers at the San Diego Zoo Institute for Conservation Research have access to so many methods and tests is because they were first developed by scientists studying human genetics!
Cytogenetics is the study of the structure and function of cells and the chromosomes within those cells. Chromosomes are bundles of genes that come in pairs, and geneticists research them so they can find out how they might affect an animal’s well-being. In cytogenetics, one of the major processes is karyotyping chromosomes, which is laying out all the chromosome in pairs and examining them. Karyotyping is important to Zoo scientists because it can determine whether an animal will have any abnormalities at birth due to their inherited genes (for example, dwarfism in California condors). This type of test is also used so human parents can find out whether or not their child will be born with disabilities such as trisomy, or Down’s syndrome, which is caused when an individual has three of the 21st chromosome instead of the usual two. Karyotyping is more difficult than it sounds. It isn’t simply laying chromosomes out in pairs and looking for irregularities—it requires a lot of hard work.
To get to an animal’s chromosomes, you need something from the animal itself that contains chromosomes, such as skin, blood, or even a feather sample. These samples must first be cultured, or grown in a special dish to allow the cells to multiply in order to be analyzed. This process includes putting the sample into a flask and giving it the right nutrients, hormones and gases. The scientists must then make sure the environment has the perfect conditions for the cells to grow, including the proper temperature. Through karyotyping, scientists may discover that an animal’s genes are valuable to the genetic variability of a species. These tissues may be stored at the Frozen Zoo®, a facility built to store and preserve valuable genetic material, where they could be used in the future to help in the conservation of endangered species.
Marisa Korody, a Research Technician at the Institute, explained the basic goals of her division and why her lab pays so much attention to chromosomes. To karyotype, Ms. Korody must break open the “box” where the chromosomes are found—the nucleus of the cell. After opening it, the chromosomes themselves are scrambled all over the place because chromosomes are not typically bound together in an organized way. Ms. Korody would then look through the chaotic jumble and find all of the chromosome pairs, ordering them from first to last. Humans have a total of 46 chromosomes, so a karyotype or complete set of chromosomes, would have 23 chromosome pairs. While the cytogeneticist who might examine human chromosomes uses the same method as Ms. Korody, the number of chromosomes varies between species. For example, California condors have 80 chromosomes. It definitely takes more time karyotyping the chromosomes of condors!
The molecular genetics division focuses on what makes animals animals—DNA. Asako Navarro, also a Research Technician in the Genetics Division at the San Diego Zoo Institute for Conservation Research, explained how DNA is used to discover the gender, species, or to identify the parents of an animal. This is vital when breeding endangered species. If two genetically similar members of the same species are matched together, there is less chance of genetic variability in the future and a greater possibility that mutations could occur. Genetic variability is an important contributor to the health of a species. Molecular geneticists use a process known as polymerase chain reaction (PCR) to get DNA from an animal or human sample. They replicate a single strand of DNA thousands of times in a matter of hours. This makes a lot of copies of the desired genes, allowing Ms. Navarro to investigate the animal’s genetic code.
In the field of genetics, we have found ways to help both animals and humans. Scientist working in the field of human genetics use the same techniques as Zoo researchers to figure out the parental identity of babies, or whether or not a baby will have a chromosomal abnormality. Molecular genetics and cytogenetics are helping scientists solve bigger problems too, such as understanding how genetic mutations cause common diseases found throughout human and animal populations. To sum it all up, these two branches of genetics are not only helping us understand ourselves and the world around us, but Zoo geneticists are becoming an important component to the health of endangered species.
Emily, Real World Team
Week Four, Winter Session 2014