The draft genome of sweet orange (Citrus sinensis) has been sequenced and analyzed, providing valuable insights into the genetic and evolutionary characteristics of this economically important fruit crop. The assembled sequence covers 87.3% of the estimated orange genome, with 20% composed of repetitive elements. The genome contains 29,445 protein-coding genes, half of which are in a heterozygous state. Comparative analyses with other citrus species suggest that sweet orange originated from a backcross hybrid between pummelo and mandarin. Gene expression analysis revealed that GalUR, encoding the rate-limiting enzyme of the galacturonate pathway, is significantly upregulated in orange fruit, suggesting a role in vitamin C metabolism. The draft genome will serve as a valuable resource for understanding and improving citrus traits in the future.The draft genome of sweet orange (Citrus sinensis) has been sequenced and analyzed, providing valuable insights into the genetic and evolutionary characteristics of this economically important fruit crop. The assembled sequence covers 87.3% of the estimated orange genome, with 20% composed of repetitive elements. The genome contains 29,445 protein-coding genes, half of which are in a heterozygous state. Comparative analyses with other citrus species suggest that sweet orange originated from a backcross hybrid between pummelo and mandarin. Gene expression analysis revealed that GalUR, encoding the rate-limiting enzyme of the galacturonate pathway, is significantly upregulated in orange fruit, suggesting a role in vitamin C metabolism. The draft genome will serve as a valuable resource for understanding and improving citrus traits in the future.