Dr. Christine Merlin, a chronobiologist in the Department of Biology at Texas A&M University, is gaining national attention for her groundbreaking research uncovering how monarch butterflies navigate thousands of miles during their annual migration. Her work was recently featured in The New York Times as part of a deep dive into the biological mystery of magnetoreception, how animals sense Earth’s magnetic field.
Dr. Merlin, a former postdoctoral researcher of renowned neurobiologist Dr. Steven Reppert, pioneered reverse genetics in monarch butterflies, allowing scientists to remove specific genes and observe how those changes affect navigation behavior. This innovative approach helped launch a new era of genetic and molecular studies in migratory insects.
Now at Texas A&M, Dr. Merlin is closing in on one of the most elusive questions in biology: what are the actual sensors that allow monarchs to detect Earth’s magnetic field?
A major milestone came in 2021, when Dr. Merlin and her team published a study in Nature Communications showing that a specific gene, CRY1, is required for the monarch’s magnetic response. The study also demonstrated that both the antennae and eyes play a role in sensing magnetic fields, narrowing down where in the butterfly’s body magnetoreception occurs.
Dr. Merlin’s research represents the “upstream” side of magnetoreception, identifying the genes, tissues, and molecular mechanisms involved in magnetic sensing. In parallel, other research teams are studying the “downstream” processes, examining how the brain interprets and integrates magnetic information once it is detected. Together, these approaches aim to answer a fundamental question: how the brain of migratory insects encodes migration.
At Texas A&M, this work is being extended by Dr. Kayla Goforth, a postdoctoral researcher in the Merlin Lab. Using CRISPR gene-editing technology, Goforth removes specific genes from monarchs and tests whether the insects can still orient using magnetic fields. By breeding monarchs lacking key genes, she is working to pinpoint the precise molecules where magnetic sensing occurs.
“My goal is to find the molecule where all of these quantum-level reactions are occurring,” Goforth said.
Beyond advancing basic biological knowledge, the implications of this research are far-reaching. Understanding magnetic navigation in monarchs could shed light on how other animals migrate, and may even inform the development of human navigation systems that do not rely on satellites.
“If you can develop a navigational tool based on Earth’s magnetic field, you can’t lose it,” Goforth said. “It’s always there.”
The research also raises intriguing questions about humans themselves.
“Do humans have a magnetic sense?” Dr. Reppert asked in the New York Times feature. “We may have a subconscious sense of Earth’s magnetic field. But there is only scant evidence of conscious perception.”