据8月28日的《科学》杂志报道说，蚕虫驯养已经有1万多年历史了。蚕为人类提供了宝贵的丝绸和蛋白。但是，现在对蚕基因进行序列测试还为人们提供了一张有关这些随时会为我们提供如此多宝贵物质的昆虫的基因变异图。
由西南大学、深圳华大基因带领的国际研究团队为29种家蚕和11种野蚕世系的基因组成功地进行了测序并找到了这些世系之间的差别。共获得了40个家蚕突变品系和中国野桑蚕的全基因组序列，共测632．5亿对碱基序列，覆盖了99．8％的基因组区域，是多细胞真核生物大规模重测序研究的首次报道；绘制完成了世界上第一张基因组水平上的蚕类单碱基遗传变异图谱，这是世界上首次报道的昆虫基因组变异图。科学家还发现了驯化对家蚕生物学影响的基因组印记，从全基因组水平上揭示了家蚕的起源进化。
研究发现，家蚕很明显地在基因上与其野生对应物不同，但即使在各家蚕世系之间，它们仍然维持着大量的变异性。这提示，家蚕只经历了一次牵涉有大量个体的单一且短暂的驯养过程，并在此后在家蚕与野蚕种群之间很少有基因流动。研究人员还能够识别出特别的能够增进丝的生产、蚕虫的繁殖和生长的基因（这些基因很可能是被人类挑选出的）。他们甚至还寻找到了在驯养过程中由蚕虫所获取的行为特征，例如极端的拥挤和容忍人的靠近和操作，以及它们在驯养过程中所丧失的如逃逸及躲避掠食者和疾病等的特征。（生物谷Bioon.com）
生物谷推荐原始出处：
Science Published Online August 27, 2009 DOI: 10.1126/science.1176620
Complete Resequencing of 40 Genomes Reveals Domestication Events and Genes in Silkworm (Bombyx)
Qingyou Xia 1, Yiran Guo 2, Ze Zhang 1, Dong Li 3, Zhaoling Xuan 2, Zhuo Li 2, Fangyin Dai 4, Yingrui Li 2, Daojun Cheng 4, Ruiqiang Li 5, Tingcai Cheng 1, Tao Jiang 2, Celine Becquet 6, Xun Xu 2, Chun Liu 4, Xingfu Zha 4, Wei Fan 2, Ying Lin 4, Yihong Shen 4, Lan Jiang 2, Jeffrey Jensen 7, Ines Hellmann 7, Si Tang 7, Ping Zhao 4, Hanfu Xu 4, Chang Yu 2, Guojie Zhang 2, Jun Li 2, Jianjun Cao 2, Shiping Liu 4, Ningjia He 4, Yan Zhou 2, Hui Liu 2, Jing Zhao 2, Chen Ye 2, Zhouhe Du 4, Guoqing Pan 4, Aichun Zhao 4, Haojing Shao 2, Wei Zeng 2, Ping Wu 2, Chunfeng Li 4, Minhui Pan 4, Jingjing Li 2, Xuyang Yin 2, Dawei Li 2, Juan Wang 2, Huisong Zheng 2, Wen Wang 2, Xiuqing Zhang 2, Songgang Li 2, Huanming Yang 2, Cheng Lu 4, Rasmus Nielsen 8, Zeyang Zhou 9, Jian Wang 2, Zhonghuai Xiang 4*, Jun Wang 5*
1 The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing 400715, China.; Institute of Agronomy and Life Sciences, Chongqing University, Chongqing 400044, China.
2 Beijing Genomics Institute at Shenzhen, Shenzhen 518083, China.
3 The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing 400715, China.; Beijing Genomics Institute at Shenzhen, Shenzhen 518083, China.
4 The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing 400715, China.
5 Beijing Genomics Institute at Shenzhen, Shenzhen 518083, China.; Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Kbh , Denmark.
6 Departments of Integrative Biology and Statistics, UC Berkeley, Berkeley, CA 94720, USA.; Present address: Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143–0794, USA.
7 Departments of Integrative Biology and Statistics, UC Berkeley, Berkeley, CA 94720, USA.
8 Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Kbh , Denmark.; Departments of Integrative Biology and Statistics, UC Berkeley, Berkeley, CA 94720, USA.
9 The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing 400715, China.; Chongqing Normal University, Chongqing 400047, China.
A single-base-pair resolution silkworm genetic variation map was constructed from 40 domesticated and wild silkworms, each sequenced to ~3X coverage, representing 99.88% of the genome. We identified ~16 million SNPs, many indels and structural variations. We find that the domesticated silkworms are clearly genetically differentiated from the wild ones, but have maintained large levels of genetic variability, suggesting a short domestication event involving a large number of individuals. We also identified signals of selection at 354 candidate genes that may have been important during domestication, some of which have enriched expression in the silk gland, midgut, and testis. These data add to our understanding of the domestication processes and may have applications in devising pest control strategies and advancing use of silkworms as efficient bioreactors.
