The standard account of embryonic development goes roughly like this: your DNA contains a program, that program gets read by transcription factors, and those transcription factors determine what kind of cell each embryonic cell becomes. It’s a compelling story. It’s also increasingly clear that it’s incomplete. A body of research now suggests that before genes are selectively activated, a pattern of electrical voltages across embryonic tissue is already sketching out the body plan — determining where the head goes, where the tail goes, and where major organs will form.
The strongest recent evidence comes from a 2024 study by Michael Levin’s lab at Tufts University, in which the team mapped the resting membrane potential of every cell in a developing frog embryo from the 32-cell stage onward. What they found was striking: voltage patterns corresponding to the future positions of the eyes, heart, and gut appeared in tissue that, at the time of measurement, was genetically undifferentiated. The electrical map came first.
The Voltage Prepattern
Using voltage-sensitive fluorescent dyes, the Tufts team imaged the membrane potential of individual cells across the entire embryo surface in real time. Distinct voltage domains — regions of consistently hyperpolarized or depolarized cells — appeared hours before the molecular markers associated with organ identity. More remarkably, when the team used pharmacological tools to scramble these voltage patterns, organ formation was disrupted even when the underlying gene expression was artificially maintained.
The genome may write the letters, but bioelectricity decides where each sentence goes on the page.
Michael Levin, Tufts University Allen Discovery Center
Implications for Birth Defects and Cancer
If bioelectric prepatterns are essential for correct organ placement, disruptions to those patterns — from environmental toxins, certain medications, or genetic mutations in ion channels — could cause developmental defects that wouldn’t show up in a standard genetic screen. Several ion channelopathies associated with congenital heart defects and heterotaxy (organs on the wrong side of the body) are now being reexamined through this lens.
What This Means For The Future
The ability to read and write bioelectric patterns in developing tissue opens the possibility of correcting body plan errors before gene expression goes wrong — a form of developmental intervention operating upstream of conventional genetic medicine. Levin’s lab has already demonstrated that externally applied voltage patterns can redirect frog embryos to grow eyes in ectopic locations, and can cause tadpoles with scrambled body plans to self-correct. The body plan, it appears, is software as much as it is hardware.
Source: Levin et al., Cell (2024) · Tufts University Allen Discovery Center for Biology-Inspired Medicine
Credit: Alex Gruber on Unsplash