GWAS analysis to resolve the key regulatory mechanism of biomineralization in Pinctada fucata martensii.

Biomineralization-controlled exo/endo-skeleton growth contributes to body growth and body size diversity. Molluscan shells undergo ectopic biomineralization to form the exo-skeleton and bio-calcified "pearl" involved in invading defence. Notably, exo/endoskeletons have a common ancestral origin, but their regulation and body growth are largely unknown. This study employed the pearl oyster, Pinctada fucata marntensii, a widely used experimental model for biomineralization in invertebrates, to perform whole-genome resequencing of 878 individuals from wild and breeding populations. This study characterised the genetic architecture of biomineralization-controlled growth and ectopic biomineralization. The IGF-like endocrine signal interacted with ancient single-copy transcription factors to from the regulatory network. Moreover, the "cross-phylum" regulation of key long non-coding RNA (lncRNA) in bivalves and mammals indicated the conserved genetic and epigenetic regulation in exo-/endoskeleton growth. Thyroid hormone signal and apoptosis regulation in pearl oysters affected ectopic biomineralization in pearl oyster. These findings provide insights into the mechanism underlying the evolution and regulation of biomineralization in exo-/endoskeleton animals and ectopic biomineralization.