Tag Archives: genetics

Poopy predators: Assessing carnivore diet and population dynamics via non-invasive genetics

Getting to the bottom of what top predators in an ecosystem are eating is critical to understand how they may be influencing dynamics in the entire system and food web. But how do you figure out what a predator is eating if it’s hard to catch and collar or watch continuously? Easy, you use their poop! Ellen Dymit, a 4^th year graduate student in the Department of Fisheries, Wildlife, and Conservation Sciences advised by Dr. Taal Levi, is our guest on the show this week and she is a poop-tracker extraordinaire!

For her PhD research, Ellen uses primarily non-invasive genetic methods to study large carnivores in two projects in Alaska and Central America. While the systems and carnivores she studies for these two projects are pretty different, the techniques she uses to analyze the collected scats are the same. The Alaska project is focused on determining what different wolf populations and packs across coastal Alaska are consuming, whether individuals are specialized in their feeding habits, and how large the populations are. The Central America project, which is based out of Guatemala, looks at a whole host of predators, including jaguars, pumas, and ocelots, to gain a better understand of the food web dynamics in the ecosystem.

One of Ellen’s extremely remote field camps in Alaska

Both of these projects involve some unique challenges in the field that Ellen has had to learn to tackle. DNA can deteriorate pretty quickly, especially in warm Guatemalan temperatures, which is problematic when you’re trying to analyze it. Yet, Ellen’s lab has perfected methods over the last few years to work with neotropical samples. Ellen’s Alaska field work is incredibly remote as it’s just Ellen and one field technician roaming the Alaskan tundra in search of wolf scat. Accessing her field sites involves being flown in on a small fixed wing plane, where they are extremely space and weight-limited. Therefore, every single piece of gear needs to be weighed to ensure that the pilot has enough fuel to get to the site and back. As a result, Ellen isn’t able to collect the entire scat samples that she finds but can only take a small, representative sample.

Ellen’s incredibly adventurous field work is followed by months spent in the lab processing her precious scat samples. So far, her results have revealed some pretty interesting differences in diet of wolf packs and populations across three field sites in Alaska. The Guatemalan project, which occurs in collaboration with the Wildlife Conservation Society Guatemala, is one of the first to analyze a large sample size of ocelot scats and the first to attempt DNA metabarcoding of samples collected in the neotropics.

To hear more details about both of these projects, as well as Ellen’s background and some bad-a$$ stories from her Alaskan field work, tune in this Sunday, October 15^th live on 88.7 FM or on the live stream. Missed the show? You can listen to the recorded episode on your preferred podcast platform!

Just keep swimming or don’t! Curiously following Zebrafish

People often think of science as focusing on very specific questions or rigorous hypothesis testing. However, some of the most exciting advancements were the result of general curiosity of seemingly disparate ideas, and a sprinkle of creativity. For example, the beginnings of how electricity was discovered started by poking frog legs with different types of metals. The modern zero-calorie sugar (saccharin) was discovered by playing creative-chef with coal tar products in the 1870’s when the chemist accidentally tasted his chemical concoction.

Sarah Alto

Our guest this week is using young zebrafish to investigate how environmental factors affect their behavior, and whether behavioral changes can be attributed to specific brain activity. Why zebrafish you may ask? They are a model organisms or they tend to be well studied, relatively easy to breed and maintain in lab settings, and as vertebrates, they share some characteristics with humans. The more we know about zebrafish, the more clues we may have into our own neurobiology. Sarah Alto is exposing these model organisms to different levels of oxygen and carbon dioxide stress. She monitors their swimming with infrared cameras and examines their brain to get an idea of how they respond to stress physically and mentally. This is no easy task because the young zebrafish are only a few millimeters long!

Oxygen, nitrogen, and carbon dioxide gas is bubbled into the tank holding the larvae.
The entire set-up is enclosed in a light-tight box so the larval behavior is more connected to the environment changes and not human interaction.

Curious Sarah is asking: Are low oxygen or high carbon dioxide concentrations changing the swimming behavior of zebrafish? What happens in the brain of a zebrafish when it experiences environmental stress? What can we learn about how environmental factors shape the brain’s connections and influence behavior? Sarah has a long road ahead of her, one that is unpaved with many junctions, but she is performing the exploratory work that may inspire future investigations into the affects of stress on the brain.

The second part of Sarah’s research will be investigating the neural activity when the larvae are exposed to the same gas concentrations as studied in the behavioral experiments.
Image courtesy of Ahrens et al. (2013)

Prior to Sara’s interest in biology, she was always drawn to art as an escape and a method of expression. When choosing which colleges to attend, she didn’t want to choose between art and science. So she chose to pursue both! Sarah enrolled at UC Berkeley as double major including Molecular and Cellular Biology, as well as Practice of Art. The San Francisco art scene was highly accessible, and Berkeley is a top-flight university for the sciences. Needless to say she flourished in this environment and her love of science grew but her love of art continues to this day. Finishing her schooling she began working at UC San Francisco, a premier medical research university, investigating the role of stem cells in facial development to for possible medical treatments for facial reconstruction. She was involved in a variety of projects but her gut feeling led her to continue schooling at Oregon State.

Sarah is now a part of Dr. James Strother’s lab in the College of Science within the department of Integrative Biology focusing the behavioral neurobiology of zebrafish. Be sure to tune in Sunday April 9^th at 7PM PST on 88.7FM or listen live.

We Answer to the Nucleotide Chain Gang

This week on Inspiration Dissemination our featured guest is our very own Zhian Kamvar aka DJ CATGAG the co-host and co-founder of our weekly broadcast. Before his radio and phytopathological fame, Zhian was an eager biologist and a DJ by a different name! All will unfold during this week’s episode, but I will supply some teasers to get the oospore rolling.

Zhian got interested in biology while in high school in California where he wanted to become a mortician…yes we all were very surprised (but not really) to learn this. Like any aspiring mortician, Zhian used the internet to find out how he should focus his studies and achieve his goal. Anatomy and Physiology were high on the list. Zhian was fascinated with many aspects of human biology particularly respiration and circulatory processes that “just happen.” For example, the human heart pump blood throughout the body 80 times per minute with no conscious intention of the individual. That was only the tip of the iceberg and his enthusiasm continued to grow while in his first genetics course in college at Truman State University in Kirksville, Missouri. This is when everything changed for Zhian and he decided to forgo his dream of becoming a mortician and focus on genetics. After a rough start at scaling the learning curve, Zhian aced Advanced Genetics and began an undergraduate research project investigating the that genes are responsible for making cultivars of corn grow and develop differently. A pivotal and proud moment for Zhian was presenting a poster at a national conference; this was only one of the many conferences that would follow.

Zhian seems very normal and boring, but wait!

Zhian poses with a petri dish containing a cultured specimen of the plant destroyer Phytophthora syringae. (Photo Credit: Lindsey Thiessen)

During his time at Truman State University, Zhian stumbled upon and promptly crashed into a gig as a radio DJ for the Truman State College Radio Station-KTRM “The Edge”. Zhian’s shows hosted the metal, vinyl, and classical genres. One of Zhian’s shows was a morning show called “Up Late with a Vampire,” a classical music hour for your morning commute in nowhere Missouri. Thus began our own DJ CATGAG’s life as a radio DJ subjecting us to his diverse musical taste. Zhian is not only a music connoisseur, from the common to the obscure, but also Zhian made and produced some of his own music, OH YES we have samples to play this Sunday! First, Zhian mixed electronic tunes as…wait for it…DJ Poopslice! Then his sound truly took form as Not Jeremy Jones where he explored harsh noise and “poplematic” (problematic pop) music.

Also, worth mentioning that after graduating from Truman State Zhian took a solo trip to Daegu, South Korean where he taught English for 3 years. In South Korea, Zhian did a lot of reading in his free time and decided he really missed participating science and research. He decided it was then time to apply to graduate school.

Zhian demonstrating functionalities of his software package, poppr, to a workshop at the American Phytopathological Society meeting in 2015 (Photo Credit: Sydney Everhart) (From twitter)

Lucky for us, (and I mean that sincerely) he was accepted to Oregon State University Department of Botany and Plant Pathology. Zhian is part of the lab of Nik Grünwald where he studies the population genetics of plant destroyers in the genus Phytophthora, specifically Phytophthora syringae and Phytophthora ramorum (this one is the pathogen responsible for Sudden Oak Death). These organisms are fungi-like and usually reproduce asexually, but they do have sex when conditions are good. His dissertation focuses on diversity of Phytophthora populations. Basically, if a population is very diversified than the effect of the pathogen on the plants involved is going to be harder to manage; whereas a population of clones may be taken out uniformly. In addition to interpreting population genetics, Zhian has been working to develop software tools that will help others to analyze data to study the genetics of other organisms. His R package called poppr allows users to analyze and visualize the distribution of genetic diversity in a population. Zhian does very great work, and we are sad to know that soon he will finish his dissertation and leave the Inspiration Dissemination team.

This is an episode you will not want to miss. Tune in at 7 pm on Sunday, August 14 to KBVR Corvallis 88.7FM or stream the show live.