A Stanford-led study of the acorn worm Schizocardium californicum discovered that during metamorphosis, most larval cells undergo extensive reprogramming rather than dying or maintaining their original functions. Researchers analyzed over 87,000 cells across five developmental stages using single-cell RNA sequencing, identifying 12 cell classes.

The findings revealed that larval cells were more similar to other larval cell types than to adult cells with identical functions. For instance, “larval neurons were more like larval gut cells than they were to adult neurons,” demonstrating widespread cellular transformation. Scientists used persistent dyes to track larval cells through metamorphosis, confirming they persisted into adulthood despite fundamental changes in identity.

Christopher Lowe, senior author and Stanford biology professor, noted that “reprogramming is a bit of an exotic fruit in developmental biology,” suggesting this mechanism may be more common in nature than previously understood. This research represents the first evidence of extensive developmental reprogramming in bilateral animals, a body plan shared with humans and other vertebrates.

The study, published in Nature Communications, compared the California acorn worm with its direct-developing cousin, the Virginia acorn worm, revealing how indirect developers with larval stages exhibit radically different cellular mechanisms during growth.

Journal: Nature Communications
DOI: 10.1038/s41467-026-77191-y
Publication Date: 8-Sep-2026

Source: EurekAlert