Chinese scientists have made new discoveries in the field of biological coloring genetic mechanism. The reporter learned from the State Key Laboratory of Silkworm Genome Biology of Southwest University that the laboratory identified the membrane transporter genes (clusters) involved in flavonoids absorption in silkworm body for the first time, revealing the genetic mechanism of silkworm green cocoon formation and cocoon color evolution. Relevant research results have been published online in the international journal Molecular Biology and Evolution recently. "The natural cocoon color of silkworm can be divided into three categories: white cocoons without or containing trace pigments; yellow-red cocoons formed by carotenoid deposition, such as golden cocoons, flesh-colored cocoons, pink cocoons, rust-colored cocoons, etc.; and green cocoons formed by flavonoids deposition." Tong Xiaoling, a professor of the State Key Laboratory of Bombyx mori Genome Biology, said that green cocoons are more difficult than other color cocoons. After degumming, the silk can still show natural green, antibacterial With stronger anti-oxidation and anti-ultraviolet properties, it has important development and utilization value. Previous studies in the scientific community have basically revealed the molecular basis of the formation of yellow-red cocoon lines, but the genetic basis of green cocoons has not been fully revealed. Through the whole-genome association analysis experiment, Tong Xiaoling and the scientific research team found a cluster of sugar transporter coding genes (Str) in tandem in the silkworm body, and participated in the absorption of flavonoids in the silkworm body through "dose sharing", thus determining the formation of green cocoons. The study of gene editing technology confirmed that the functional defect of this cluster of Strs would lead to the reduction of the content of flavonoids in the silk gland and cocoon of the silkworm, and the color of the cocoon would become lighter. The research team also analyzed the formation mechanism of cocoon color diversity based on the pan-genome system, proposed the cocoon color evolution model from wild silkworm to silkworm, and revealed the genetic mystery of cocoon. "Analyzing the mechanism of green cocoon formation has important practical significance for breeding and creating new silkworm varieties with high quality and high added value." Dai Fangyin, the chief scientist of the national sericulture industry technology system and professor of Southwest University, said that the flavonoids that form green cocoons play an important role in human health. The research results on the mechanism of green cocoon formation of silkworm, It also has reference value for the absorption and utilization of flavonoids in animals and humans. (Outlook New Era)