This piece is part of a series tracing new specimens and tissues brought into the Invertebrate Zoology (IZ) department from the field. Here, support scientist Herman Wirshing discusses his role in current molecular analysis work in IZ. Additionally, Herman shares a bit about his background and how his career path led him to the Laboratories of Analytical Biology (LAB) at the Smithsonian.
What is molecular analysis?
In the field of modern natural history museum curation and research, it’s no longer enough to store specimens for studies of morphology (the form and structure of an organism). Today, questions regarding biodiversity, ecology, and evolution are also explored by investigating the genetic makeup of the organism. When new specimens are brought into the National Museum of Natural History (NMNH), small pieces of tissue from these organisms are frequently removed to harvest their genetic material in the lab.
To study an organism’s genetic makeup, you typically sequence some piece of the organism’s genome, which is the complete copy of all of the genetic material (DNA) in that organism. Tissue samples must be processed according to a sequence of steps before any DNA can be sequenced. First, the tissues are chemically digested to extract and isolate the DNA. Next, in a process referred to as amplification, millions of copies of the gene of interest are generated using a technique called polymerase chain reaction (PCR). Lastly, the amplicons (the millions of gene copies generated by PCR) are sequenced. This process reveals each DNA “letter,” or base pair (A, G, T, or C), that makes up the gene. The sequenced genes can then be compared to sequences from other species.
Herman notes that a lot of challenges can arise along the way. For example, in instances of symbiosis, such as an algal species living symbiotically with a coral or a hydroid with a polychaete, the wrong DNA can accidentally be sequenced. Thankfully, Herman is very skilled in these techniques and has a quick eye for spotting problems and figuring out ways around them.
Some of Herman’s current work
One of Herman’s current projects at NMNH is the molecular analysis of polychaete specimens (example pictured) recovered by research zoologist Karen Osborn on her recent cruise aboard the Monterey Bay Aquarium Research Institute’s R/V Western Flyer.
“Under the umbrella of biodiversity, we’re looking at how diverse these worms are in their open water environment, and how the different groups and populations of worms are structured, not only horizontally, but vertically as well. For example, when we think of population structure on land, it’s horizontal, because species spread out across the land’s surface. But in the ocean, there’s depth to consider, so a worm population in the middle of the ocean can also spread vertically,” explains Herman.
Hence, molecular analyses of polychaetes recovered from different depths not only shed light on which populations are present but also at what depths individual species reside. Amusingly, the genes that are most important to this type of work can be considered “biologically boring,” that is, “they evolved neutrally, so that as populations split, different genetic variations accumulated largely by chance in distinct populations. This process allows us to use these genes to determine how closely or distantly related the various polychaete populations and species are,” Herman relates.
Why molecular analysis is so important to ocean research
When asked to explain why molecular analysis is important in the big picture sense, Herman says that “ultimately, molecular analyses are used to set foundations of knowledge, such as how diverse environments are in terms of species. This information can be used to address questions of how diversity is changing over time. For example, we may ask questions like, can knowledge of the organisms currently living in a given environment help us make recommendations on how to better manage these areas?”
Of course, many other researchers in IZ carry out molecular analyses of their respective invertebrates of interest. And many, many other researchers in other departments at NMNH also use molecular analyses to learn more about the biodiversity and populations of insects (Entomology), vertebrates (Vertebrate Zoology), and plants (Botany). Clearly, this type of work is crucially important to modern biodiversity research, which is why it is a good thing that the LAB has someone as knowledgeable and skilled as Herman (and its many other scientists!) working in its ranks.
Say “hello” to Herman
As an undergraduate, Herman initially thought he would pursue a career in the medical field. However, after he took courses in developmental biology and marine biology, Herman realized that he “liked those areas a lot more.” Hence, in his last year of undergraduate studies, Herman pursued a directed independent study with a faculty member on the symbiosis between sea anemones and anemone fish.
Then, immediately following his bachelor’s degree, Herman took a job as an aquarist, where he was exposed to many different marine organisms, but realized that he “wanted to know more about the academic side of marine science.” So he went back to school for a master’s at Nova Southeastern University, during which he focused on coral reef ecology, performing research that allowed him to develop specialty skills in coral systematics, genetics, and taxonomy. These lab skills were particularly helpful in terms of Herman attaining his next position as a lab manager at Columbia University in New York.
The principal investigator of that lab, Andrew Baker, later accepted a tenure track position at the Rosenstiel School of Marine and Atmospheric Science at the University of Miami, and took Herman with him – this time, as a doctoral graduate student. Having previously visited IZ research zoologist Steve Cairns here at NMNH, Herman “knew that the museum could be a good fit, plus [at the end of my doctoral studies] the LAB had just opened at NMNH, so I consulted museum research zoologists Christopher Meyer and Steve to see if I could find a way to become involved with both sides of my research, so that I could continue doing genetic work, as well as work with octocorals.”
Now that he’s here, Herman says “the best part is the freedom to get involved in other things that go beyond the typical lab duties, being able to be creative about the research process, as well as doing analyses, coming up with different projects, and collaborating with the curators. We’re always communicating about new ideas.”
by Liz Boatman
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