Science：玉米B73系基因组序列

专题：Science报道

据11月20日的《科学》杂志报道说，玉米自交系B73的基因组序列测定是由Patrick Schnable及其同僚完成的。这一序列测定应该能够帮助解答许多长期存在的疑问，其中包括被称作转位因子的可移动DNA序列的影响以及现代玉米的基因组是如何从2个先祖基因组的融合演化而成的。 B73常常被用来繁殖新的饲用玉米系列，因此其基因组的测序应该还能够为人们提供基因标记，帮助植物栽培者或种子公司开发细心打造的作物：例如，这些作物可有更高的营养含量或需要较少的化肥。

研究人员发现并定位了超过3万2000个基因。他们确认，该基因组中有近85%是由数百个转位因子族所组成的。 这些因子影响着着丝点（即每条染色体的2个单体的连接点，它们在细胞分裂中起着一种关键性的作用）的组成、大小和位置。 文章的作者还描述了在基因组重复区域中的基因丢失为什么最可能是与该作物远古状态时染色体拷贝数从4条减少至2条的原因。

研究人员写到：B37玉米系的序列“有可能会促进基础研究并推动人们在全球气候变迁时期满足全世界对食物、饲料、能源及工业原料不断增长的需求。”（生物谷Bioon.com）

生物谷推荐原始出处：

Science 20 November 2009: DOI: 10.1126/science.1178534

The B73 Maize Genome: Complexity, Diversity, and Dynamics

We report an improved draft nucleotide sequence of the 2.3-gigabase genome of maize, an important crop plant and model for biological research. Over 32,000 genes were predicted, of which 99.8% were placed on reference chromosomes. Nearly 85% of the genome is composed of hundreds of families of transposable elements, dispersed nonuniformly across the genome. These were responsible for the capture and amplification of numerous gene fragments and affect the composition, sizes, and positions of centromeres. We also report on the correlation of methylation-poor regions with Mu transposon insertions and recombination, and copy number variants with insertions and/or deletions, as well as how uneven gene losses between duplicated regions were involved in returning an ancient allotetraploid to a genetically diploid state. These analyses inform and set the stage for further investigations to improve our understanding of the domestication and agricultural improvements of maize.