Tiny dwarf male barnacles act as sperm donors while their cells remain genetically identical to females.
April 25, 2026
Original Paper
Dwarf males function as males but retain female-biased transcriptional profiles in an androdioecious barnacle
EcoEvoRxiv · 10.32942/X2HD4X
The Takeaway
In certain barnacle species, some individuals take on the role of a male but never develop the full genetic signature associated with that sex. These dwarf males possess functional male organs yet their gene expression profiles are almost indistinguishable from female tissues. This biological mismatch challenges the idea that an organism must transition its entire transcriptional profile to change its reproductive role. It shows that the biological wiring of an animal can operate independently of its outward sexual behavior. This finding opens new questions about the flexibility of sex determination and development in the animal kingdom. The organism performs one biological role while its genes are busy reading the script for another.
From the abstract
Sexual systems exhibit remarkable diversity, yet how alternative reproductive strategies are implemented at the level of gene expression remains poorly understood. In androdioecious species, males coexist with hermaphrodites and function exclusively as sperm donors, raising the question of whether the males’ transcriptional profiles are fully masculinized or retain features of hermaphroditic ancestry. We investigated this question in the epizoic barnacle Octolasmis unguisiformis by comparing tra