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bioRxiv · 10.64898/2026.07.14.736884

Magnetosensitivity of amphibian morphological pigmentation is light- and eye-dependent and consistent with the radical pair mechanism

Zadeh-Haghighi, H.·Bertolesi, G. E.·McFarlane, S.·Simon, C.
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Abstract

Weak magnetic fields influence a wide range of biological processes, yet the underlying mechanisms are poorly understood. The radical pair mechanism (RPM), which involves quantum spin dynamics, is a leading hypothesis. Here we show that weak magnetic fields modulate morphological pigmentation--specifically, the number of perioptic melanophores-- in Xenopus laevis tadpoles in a field-strength-dependent manner. The response is light- and eye-dependent. The observed field-strength dependence is quantitatively consistent with a radical pair model. These properties are reminiscent of the light-dependent magnetoreception that is thought to operate in migratory birds, and establish amphibian pigmentation as a tractable vertebrate system for the study of radical-pair quantum biology. Significance statementWhether weak magnetic fields can influence vertebrate physiology through quantum spin dynamics has been difficult to test in a living animal. We show that weak magnetic fields alter the number of perioptic melanophores in Xenopus laevis tadpoles through a light- and eye-dependent mechanism whose field-strength dependence is quantitatively consistent with a radical-pair mechanism. Amphibian pigmentation thus offers a genetically tractable vertebrate system in which radical-pair quantum biology can be tested against whole-organism physiology.

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Zadeh-Haghighi, H., Bertolesi, G. E., McFarlane, S., Simon, C.. 2026-07-16. Magnetosensitivity of amphibian morphological pigmentation is light- and eye-dependent and consistent with the radical pair mechanism. https://doi.org/10.64898/2026.07.14.736884

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