How Sponges Evolved to Build with Glass
A new study in Molecular Biology and Evolution reconstructs the evolutionary history of silicon transport and skeleton formation in sponges, revealing a story of adaptation, coevolution, and convergent evolution. Researchers show that the molecular machinery for silicic acid uptake—a partnership between aquaglyceroporin channels (gAQP) and arsenite efflux pumps (ArsB)—originated in prokaryotes and was present in ancestral sponges long before the first silica skeletons appeared in the fossil record. Through phylogenetic analysis of hundreds of sequences, the work demonstrates remarkable coevolution between these transporters in some lineages, punctuated by horizontal gene transfer events that coincided with major diversifications. Crucially, lineages that never evolved or later lost the ability to polymerize silica also lost their gAQP genes, indicating strong selective pressure against passive silicon influx without the machinery to use it. This suggests that the ability to form a silica skeleton likely evolved independently at least four times as an adaptive response to the toxic, high-silicon conditions of the Precambrian oceans.
Study Significance: This research provides a powerful case study in molecular adaptation and the repeated evolution of complex traits. For evolutionary biologists, it underscores how ancient environmental pressures can drive the convergent evolution of key innovations like skeletal biomineralization. The findings directly connect genetic changes in transporter proteins to macroevolutionary patterns of diversification and extinction, offering a detailed framework for understanding how selective pressures shape functional genomics and phenotypic radiation across deep time.
Source →Stay curious. Stay informed — with Science Briefing.
Always double check the original article for accuracy.
