Ancient Myosin Gene Variant Controls Left-Right Shell Coiling in Japanese Snails
Researchers identified a genetic polymorphism in myosin I a/b that determines whether Japanese Euhadra snails develop left-coiling (sinistral) or right-coiling (dextral) shells. The two gene variants are ancient, cause minimal differences in early embryonic gene expression, and are not associated with disease, unlike similar mutations in other snail species. This discovery expands understanding of how left-right asymmetry develops in animals and identifies snails as a valuable model organism for studying this fundamental developmental process.
A new study published on bioRxiv reveals that chiral polymorphism in Japanese Euhadra snails—the variation in shell coiling direction—stems from functional differences in an unconventional myosin I a/b protein. Both the sinistral (left-coiling) and dextral (right-coiling) gene variants are evolutionarily ancient and produce only minimal differences in transcription during single-cell embryonic stages, distinguishing them from pathological chirality mutations found in other snail species. Using phylogenetic analysis and structural modeling, the researchers determined that dominant-acting amino acid substitutions in the myosin actin-binding domain and motor-level junction were likely enabled by relaxed evolutionary selection. The findings broaden the known molecular mechanisms controlling left-right asymmetry—a fundamental feature of animal development—and suggest specific mutations and positions worth investigating in other model organisms. The work positions snails as a powerful experimental system for understanding how left-right asymmetry originates in animals.
What different sources said
- bioRxivCenter
An ancient polymorphism in myosin I a/b determines the left-right asymmetry of Japanese snails
Related
Genetic Drift, Not Selection, Drives Rapid Feather Color Evolution in Island Bird Radiation
A new study of an island bird radiation found that rapid evolution of feather coloration is driven primarily by genetic drift in small populations rather than sexual or ecological selection. The research integrated whole-genome data with detailed plumage measurements across complete species sampling to test whether signaling trait evolution correlates with speciation rates. The findings suggest that neutral demographic processes play a central role in generating phenotypic diversity during island radiations, challenging assumptions about the mechanisms driving rapid evolution.
New AI Model Improves Prediction of Therapeutic Peptide Function from Protein Sequences
Researchers developed a lightweight CNN classifier that predicts whether peptide sequences have therapeutic properties, trained on a database of 54,655 peptides across 48 functional categories. The model uses a novel negative sampling strategy to reduce false positive rates from over 60% in previous approaches to 2.1%. This advancement could accelerate drug discovery by enabling faster computational screening of peptide candidates before expensive experimental testing.
Study Shows Different Metabolic Stress Models Produce Distinct Effects on Human Neuronal Networks
Researchers tested three common in vitro metabolic stress models on human-derived neuronal networks and found each produced different patterns of neuronal activity and cell damage. The models tested were hypoxia alone, oxygen-glucose deprivation (OGD), and hypoxia combined with glutamate exposure. The findings suggest that choice of experimental model significantly affects results and that combining electrophysiological and structural analyses is important for accurately assessing metabolic stress in stroke research.