继2003年率先完成世界第一个家蚕基因框架图后,由中国工程院院士向仲怀率领的西南大学家蚕研究团队又成功绘制完成了家蚕全基因组精细图谱,并成功开发出我国第一个转基因新型有色茧实用蚕种。研究团队与广西蚕业技术推广总站合作育成的一对新品种,能结出色彩稳定的绿色茧。用这种茧缫出的生丝在自然光线下呈现美丽的绿色,在紫外光下还能发出绚丽的绿色荧光。
家蚕是迄今唯一被人类完全驯化的经济昆虫,是国际公认的鳞翅目昆虫研究模式。我国科学家于2003年成功绘制的世界第一家家蚕基因框架图,也是世界第一张鳞翅目昆虫基因组图谱,被誉为21世纪蚕业科学的里程碑。
据研究团队的夏庆友教授介绍,家蚕基因精细图谱是继框架图后,再次取得的家蚕基因组研究的世界领先成果和重大贡献。这一成果使得研究人员能在基因组水平上更加详细、全面分析家蚕基因的表达特征、鉴定与特定生命现象相关的功能基因群,为阐明家蚕基因基本生物学性状的遗传基础,识别、筛选具有重要经济价值的功能基因提供了重要支撑。随着家蚕基因组精细图的完成,研究人员能够更深入地认识家蚕吐丝、食性、发育及变态等特异的生物学过程。这一重大研究成果受到了国际昆虫学界的高度评价,最权威的国际昆虫学杂志为此专门出版《家蚕基因组特别刊》,报道了包括精细图成果在内的15篇研究论文。研究团队首次绘制出的蚕类基因组变异图谱,第一次在全基因组水平上分析了家蚕的起源进化关系,表明家蚕起源于中国野蚕。
夏庆友说,蚕类基因组变异图谱是迄今为止最为详尽、最具应用价值的昆虫基因组遗传多态性图谱,研究人员因此可以更加便捷和准确地对家蚕重要经济性状相关基因进行大规模筛选、定位克隆和功能研究。
研究团队成功建立了高效、实用的家蚕转基因技术体系,并在此基础上开发出了转基因新型有色茧开发技术和我国第一个转基因新型有色茧实用蚕品种。用新型绿色茧缫出的蚕丝,是我国首次获得转基因新型蚕丝。这是天然彩色丝的突破,标志着利用转基因技术改造蚕丝结构,克服蚕丝易皱、褪色等先天缺陷的新型素材创新工程进入了一个新的阶段,将对蚕丝业产生重大影响。（生物谷Bioon.com）
生物谷推荐原始出处：
Insect Biochemistry and Molecular Biology, Available online 16 December 2008
The genome of a lepidopteran model insect, the silkworm Bombyx mori
Zhonghuai Xiang, Kasuei Mita, Qingyou Xia, Jian Wang, Shinshi Morishita, Toru Shimada
Bombyx mori, the domesticated silkworm, is a major insect model for research, and the first lepidopteran for which draft genome sequences became available in 2004. Two independent datasets from whole-genome shotgun sequencing were merged and assembled together with newly obtained fosmid- and BAC-end sequences. The remarkably improved new assembly is presented here. The 8.5 fold sequence coverage of an estimated 432 Mb genome was assembled into scaffolds with a N50 size of ~3.7 Mb; the largest scaffold was 14.5 million base pairs. With help of a high density SNP linkage map, we anchored 87% of the scaffold sequences to all 28 chromosomes. A particular feature was the high repetitive sequence content estimated to be 43.6% and that consisted mainly of transposable elements. We predicted 14,623 gene models based on a GLEAN-based algorithm, a more accurate prediction than the previous gene models for this species. Over three thousand silkworm genes have no homologs in other insect or vertebrate genomes. Some insights into gene evolution and into characteristic biological processes are presented here and in other papers in this issue. The massive silk production correlates with the existence of specific tRNA clusters, and of several sericin genes assembled in a cluster. The silkworm's adaptation to feeding on mulberry leaves, which contain toxic alkaloids, is likely linked to the presence of new-type sucrase genes, apparently acquired from bacteria. The silkworm genome also revealed the cascade of genes involved in the juvenile hormone biosynthesis pathway, and a large number of cuticular protein genes.
