繼2003年率先完成世界第一個家蠶基因框架圖后,由中國工程院院士向仲懷率領的西南大學家蠶研究團隊又成功繪制完成了家蠶全基因組精細圖譜,并成功開發(fā)出我國第一個轉(zhuǎn)基因新型有色繭實用蠶種,。研究團隊與廣西蠶業(yè)技術推廣總站合作育成的一對新品種,能結(jié)出色彩穩(wěn)定的綠色繭。用這種繭繅出的生絲在自然光線下呈現(xiàn)美麗的綠色,在紫外光下還能發(fā)出絢麗的綠色熒光,。
家蠶是迄今唯一被人類完全馴化的經(jīng)濟昆蟲,是國際公認的鱗翅目昆蟲研究模式,。我國科學家于2003年成功繪制的世界第一家家蠶基因框架圖,也是世界第一張鱗翅目昆蟲基因組圖譜,被譽為21世紀蠶業(yè)科學的里程碑。
據(jù)研究團隊的夏慶友教授介紹,家蠶基因精細圖譜是繼框架圖后,再次取得的家蠶基因組研究的世界領先成果和重大貢獻,。這一成果使得研究人員能在基因組水平上更加詳細,、全面分析家蠶基因的表達特征、鑒定與特定生命現(xiàn)象相關的功能基因群,為闡明家蠶基因基本生物學性狀的遺傳基礎,識別,、篩選具有重要經(jīng)濟價值的功能基因提供了重要支撐,。隨著家蠶基因組精細圖的完成,研究人員能夠更深入地認識家蠶吐絲、食性,、發(fā)育及變態(tài)等特異的生物學過程,。這一重大研究成果受到了國際昆蟲學界的高度評價,最權威的國際昆蟲學雜志為此專門出版《家蠶基因組特別刊》,報道了包括精細圖成果在內(nèi)的15篇研究論文。研究團隊首次繪制出的蠶類基因組變異圖譜,第一次在全基因組水平上分析了家蠶的起源進化關系,表明家蠶起源于中國野蠶,。
夏慶友說,蠶類基因組變異圖譜是迄今為止最為詳盡,、最具應用價值的昆蟲基因組遺傳多態(tài)性圖譜,研究人員因此可以更加便捷和準確地對家蠶重要經(jīng)濟性狀相關基因進行大規(guī)模篩選、定位克隆和功能研究,。
研究團隊成功建立了高效,、實用的家蠶轉(zhuǎn)基因技術體系,并在此基礎上開發(fā)出了轉(zhuǎn)基因新型有色繭開發(fā)技術和我國第一個轉(zhuǎn)基因新型有色繭實用蠶品種。用新型綠色繭繅出的蠶絲,是我國首次獲得轉(zhuǎn)基因新型蠶絲,。這是天然彩色絲的突破,標志著利用轉(zhuǎn)基因技術改造蠶絲結(jié)構(gòu),克服蠶絲易皺,、褪色等先天缺陷的新型素材創(chuàng)新工程進入了一個新的階段,將對蠶絲業(yè)產(chǎn)生重大影響。（生物谷Bioon.com）
生物谷推薦原始出處：
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.
