Fruit fly embryos naturally try to grow in a spiral, but their eggshells force them to stay straight.
April 1, 2026
Original Paper
Embryo-eggshell interaction counteracts chiral bias in early Drosophila morphogenesis
bioRxiv · 10.64898/2026.03.25.714261
The Takeaway
Scientists discovered that developing embryos have an inherent 'handedness' that makes them want to twist like a screw. They only develop a straight, symmetrical body plan because the friction and physical constraint of the surrounding eggshell act as a mold to keep them in place.
From the abstract
Morphogenetic processes during animal development are remarkably invariant (Duboule, 1994; Hall, 1997; Kalinka et al., 2010; Raff, 1996). This stability is established by the interaction between genetic determination of developmental progression and the constraints imposed by the surrounding embryonic environment (Busby and Steventon, 2021; Gilmour et al., 2017; Gorfinkiel and Martinez Arias, 2021). We discovered that the germ band extension process in Drosophila is rather variable: instead of e