Mapping the mosquito genome to fight malaria

There is currently no cure for malaria, which killed an estimated 619,000 people worldwide in 2021 and sickened some 247 million more. With the progress of globalization and climate change — and the presence of potentially disease-carrying mosquitoes — there are signs malaria may even make a comeback in North America, where it was eradicated back in 1951.

Now, Exeter students have joined ongoing research efforts aimed at fighting the spread of malaria worldwide. In a new biology course developed by Science Instructors Dr. Shimaa Ghazal and Anne Rankin ’92 and taught by Dr. Ghazal, students succeeded in mapping a full genome sequence for a strain of the mosquito species Anopheles gambiae, a leading host for the parasite that causes malaria. The results of their efforts were published last month in GenBank, the National Institutes of Health’s annotated database of all publicly available DNA sequences.

To carry out this real-world research, Dr. Ghazal and her students worked in collaboration with laboratories run by Dr. Seung Kim ’81 at Stanford University and Dr. Michael Povelones at PennVet, the University of Pennsylvania’s School of Veterinary Medicine. Dubbed “PEA_Agam_2022” (for “Phillips Exeter Academy, Anopheles gambiae, winter 2022”), the newly mapped genome is one of only seven for Anopheles gambiae that are published in the GenBank and the first to be published by a high school; the six others are from universities and labs in the United States and abroad.

As Anopheles gambiae is one of the leading vectors for malaria, scientists like Kim and Povelones focus on studying the genetic makeup of different strains of the species. By pinpointing genetic material that makes the mosquitoes better or worse at carrying the disease, they hope to develop more effective insecticides and maybe even — one day — create mosquitoes that are resistant to carrying malaria.

In addition to the complex “wet lab” work involved in preparing the tiny snippets of mosquito DNA for sequencing, students in the new course read and discussed journalist Sonia Shah’s book The Fever: How Malaria Has Ruled Humankind for 500,000 Years. “We wanted to put the disease into a broader context, and broaden the students’ understanding,” Rankin says. “We sequenced a genome, but we did not just sequence a genome — we learned a lot about the context of malaria in different parts of the world, and the way it has influenced human history.”

The “malaria course,” offered in the winter term last year, will return in spring 2024 as BIO 650: Exploring Bioinformatics and Next-Generation Sequencing. It builds on the model of Exeter’s popular “fruit fly course,” part of a long-running collaboration with Kim’s lab at Stanford launched in 2012. Students enrolled in that course, BIO 586: Molecular Genetics, first sequenced the genome of Drosophila melanogaster, the common fruit fly, back in 2019. In addition to the wet lab work, BIO 650 also introduces students to the growing interdisciplinary field of bioinformatics, which applies computer technology to understand biological data and information.