Baoyue Lu | Search PubMed

PubMed2026

Chromosome-level genome assembly of the horned turban snail Turbo cornutus.

The horned turban snail (Turbo cornutus) is an ecologically and economically important herbivorous gastropod inhabiting nearshore rocky reef habitats. T. cornutus represents a valuable coastal fishery resource in East Asia. Here, we present a chromosome-level genome assembly for T. cornutus generated using a combination of PacBio HiFi long-read and Illumina short-read sequencing and Hi-C scaffolding. The assembled genome spanned 1.93 Gb and was organized into 18 pseudo-chromosomes, representing 99.50% of the total assembly. The contig and scaffold N50 lengths were 41.02 Mb and 104.01 Mb, respectively, with repeat sequences constituting 59.07% of the genome. A total of 28,920 protein-coding genes were predicted, and genome completeness was assessed at 99.3% using the BUSCO mollusca_odb12 dataset. This chromosome-level genome assembly provides a reference for future studies on the biology of T. cornutus, the organization of the gastropod genome, and comparative genomics.

Animals↗

PubMed2026

A duplicated female pathway gene figla-like evolves as the male sex-determining gene in tilapia.

As the largest group of vertebrates, fish exhibit frequent turnover of sex-determining (SD) genes. Here, we assemble a chromosome-level YY red tilapia genome and identify figla-like (figlal) as the SD gene on tilapia linkage group (LG) 1. Integrative phylogenetic and genomic evidence suggests that figlal originated from a tilapia-specific duplication and transposition of the ancestral bHLH family gene figla from LG12 to LG1. Fluorescence in situ hybridization reveals expression divergence between figla and figlal, with figla expressed in female oocytes and figlal expressed in male gonadal somatic cells during early gonadal differentiation. The shift in expression after duplication might be driven by the insertion of cis-regulatory elements mediated by transposable elements. Knockout of figlal in XY fish results in male-to-female sex reversal as indicated by ovarian morphology, down-regulation of the male pathway gene dmrt1, and up-regulation of the female pathway gene cyp19a1a in the gonads. In contrast, overexpression of figlal in XX fish induces female-to-male sex reversal. These findings implicate figlal as an SD gene on tilapia LG1 and reveal the history of a unique evolutionary innovation in which a female oocyte gene evolved into a male SD gene via duplication, transposition, and cis-regulatory rewiring.

Animals↗