The c.503A>G polymorphism in ZIP1-II of Pacific oyster Crassostrea gigas associated with zinc content.

The Pacific oyster Crassostrea gigas is renowned for its high zinc content, but the significant variation among individuals diminishes its value as a reliable source of zinc supplementation. The Zrt/Irt-like protein 1 (ZIP1), a pivotal zinc transporter that facilitates zinc uptake in various organisms, plays crucial roles in regulating zinc content. In the present study, polymorphisms of a ZIP1 gene in C. gigas (CgZIP1-II) were investigated, and their association with zinc content was evaluated through preliminary association analysis in 41 oysters and verification analysis in another 200 oysters. A total of 17 single nucleotide polymorphisms (SNPs) were identified in the exonic region of CgZIP1-II gene, with c.503A>G significantly associated with zinc content. Protein sequence and structure prediction showed that c.503A>G caused a p.Met110Val nonsynonymous mutation located in the metal-binding region of CgZIP1-II, which could influence its affinity for zinc ions, thereby modulating its zinc transport functionality. These results indicate the potential influence of CgZIP1-II polymorphisms on zinc content and provide candidate markers for selecting C. gigas with high zinc content.