Genomes of Solenogastres Shed Light on Ancestral Molluscan Biomineralization Genes
- 1The University of Alabama
Abstract
Aplacophora (Solenogastres + Caudofoveata) is a group of worm-like molluscs that lack a shell and instead are covered with aragonitic spines and scales called sclerites. Sclerites are also found along the girdle in chitons (Polyplacophora) and are a synapomorphy for Aculifera (Aplacophora + Polyplacophora), which is the sister taxon of all other shell-bearing molluscs (Conchifera). However, whether the same genetic mechanism underlies the process of biomineralization in aculiferans and conchiferans is unknown. To investigate evolution of genes involved in biomineralization across Mollusca, we re-sequenced the genomes of two species of Solenogastres, Epimenia babai and Neomenia megatrapezata, producing near-chromosome-level assemblies through PacBio HiFi and Hi-C scaffolding. Using a combination of orthology inference and similarity searches against a known SMP database we identified 1,244 putative SMP orthogroups across Mollusca, 292 of which were present in at least one solenogaster genome. SMPs undergoing significant expansion/contraction at key nodes were further investigated. Of these, 15 were found in at least one solenogaster genome and included families containing chitin-binding, von Willebrand factor A, and C-type lectin domains. Across Mollusca, Solenogastres showed the highest number of significant losses in all gene families, including the SMPs investigated. Targeted searches for structural, silk-like proteins in Aculifera show further reductions in Solenogastres (16-17) compared to caudofoveates (29) and chitons (46-80). Altogether, our results support a conserved but reduced biomineralization toolkit underlying sclerite formation in Solenogastres and identify candidate genes for further proteomic and functional study.
Related
- Living representatives of the spiralian ancestral karyotype revealed by two Lima genomes
- Barking Up Inferred Trees: Detecting Signatures of Selection in Dog Genomes Using Ancestral Recombination Graphs
- Reconstruction of ancestral plant genomes for inter-crop translational research
- Molecular dynamics insights into biomineralisation mediated by acidic intrinsically disordered proteins: a case study of molluscan Aspein from the pearl oyster Pinctada fucata
- Novel Antarctic chemolithotroph drives iron biomineralization
BibTeX
@misc{yapchiongco2026genomes,
title = {{Genomes of Solenogastres Shed Light on Ancestral Molluscan Biomineralization Genes}},
author = {M. Yap-Chiongco and K. M. Kocot},
howpublished = {bioRxiv},
year = {2026},
month = nov,
doi = {10.64898/2026.11.06.764910},
url = {https://www.biorxiv.org/content/10.64898/2026.11.06.764910v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Genomes of Solenogastres Shed Light on Ancestral Molluscan Biomineralization Genes
AU - M. Yap-Chiongco
AU - K. M. Kocot
PY - 2026
DA - 2026/11/06
PB - bioRxiv
DO - 10.64898/2026.11.06.764910
UR - https://www.biorxiv.org/content/10.64898/2026.11.06.764910v1
AB - Aplacophora (Solenogastres + Caudofoveata) is a group of worm-like molluscs that lack a shell and instead are covered with aragonitic spines and scales called sclerites. Sclerites are also found along the girdle in chitons (Polyplacophora) and are a synapomorphy for Aculifera (Aplacophora + Polyplacophora), which is the sister taxon of all other shell-bearing molluscs (Conchifera). However, whether the same genetic mechanism underlies the process of biomineralization in aculiferans and conchiferans is unknown. To investigate evolution of genes involved in biomineralization across Mollusca, we re-sequenced the genomes of two species of Solenogastres, Epimenia babai and Neomenia megatrapezata, producing near-chromosome-level assemblies through PacBio HiFi and Hi-C scaffolding. Using a combination of orthology inference and similarity searches against a known SMP database we identified 1,244 putative SMP orthogroups across Mollusca, 292 of which were present in at least one solenogaster genome. SMPs undergoing significant expansion/contraction at key nodes were further investigated. Of these, 15 were found in at least one solenogaster genome and included families containing chitin-binding, von Willebrand factor A, and C-type lectin domains. Across Mollusca, Solenogastres showed the highest number of significant losses in all gene families, including the SMPs investigated. Targeted searches for structural, silk-like proteins in Aculifera show further reductions in Solenogastres (16-17) compared to caudofoveates (29) and chitons (46-80). Altogether, our results support a conserved but reduced biomineralization toolkit underlying sclerite formation in Solenogastres and identify candidate genes for further proteomic and functional study.
ER -