Parasitic Science

Although parasitoid wasps are multicellular organisms, there is one species so small, that some bacteria are larger than it. University of California, Riverside’s Department of Entomology currently researches this species and attempting to classify them. Chaffey College student Houssam Nassser is an intern at the program and assists in the molecular work concerning the wasps so they may be further studied and classified.

Currently, the lab is studying Chalcidoidea wasps, which lay their parasites in other wasps. The wasp that lays parasites smaller than single cellular organisms is known as mymaridae. It can be as small as 0.013 millimeters. Brody Salazar @Brody_Salazar

Houssam Nasser using a centrifuge. Photos by Brody Salazar.

Krissy Dominguez showing DNA sequences.

Even though many people do not think of molecular information as being closely related to the topic of entomology, it occupies a good deal of the lab’s time. This is because the molecular work isolates and examines gene regions and can be used to properly identify the insects, especially in relation to others, and understand them.

“We’re taking specific gene regions,” says Nasser’s supervisor Krissy Dominguez, “and… we do PCR, we also do next generation sequencing techniques, and we build phylogenetic trees, so like trees of life. We learn how these really important biological control wasps are related to one another. And that gives us a heads up on their evolution and an understanding host associations, behavior, all of which are critically important to agriculture in California and releasing natural enemies to go after pest insects.”

Despite the development of molecular work, morphology is still a part of entomology, so the department employs both methods of study, albeit with less of an emphasis on morphology.

A large parasitoid wasp.

“You use a bunch of different chemicals, I would say, or reagents, and one of them is polymerase,” says Nasser. “You have the original DNA template, right? So, what you do through this process is you make copies of this one single DNA...the reason why you do that is, when we do the sequencing they have to be amplified so the machine can handle them.”

Once the DNA sequences have been duplicated via PCR, it is sent to a different lab where it goes through the process of sequencing, which is used to identify what nucleotides are in the DNA. When the process is finished, the information is sent back, and the lab analyzes the genes of other insects for comparison. Nasser describes the whole internship as being enjoyable, in part because he was given tasks that he enjoyed, but he finds PCR to be his favorite. He appreciates that he is learning new skills that he can use later in life both in university and his desired career.

“In general, overall, the internship is not difficult at all. It’s fun,” says Nasser. Dominguez stated the emphasis for the internship was on the former rather than the latter because it would apply more to him.

Nasser’s interest in molecular work is of both personal and occupational. He describes his work with genetic material as being beneficial to him as both a biology major and someone interested in the medical field.

“We are made of cells, and our cells have DNA, right,” says Nasser. “So, I have to get familiar with how to use this DNA because there is a part of medicine called pathology…They look at the different cells, and they use DNA sometimes to diagnose either new diseases or a normal disease, but you can’t detect it unless you studied DNA. So DNA is everywhere in the medical field.”

Nasser’s work in the lab involves DNA extraction, cleaning and polymerase chain reaction, or PCR. PCR is a method of duplicating a segment of DNA and is a necessary step in examining DNA, as it helps the machines process the data.

Nasser incubating specimens.