Messing Joachim, Dooner Hugo K
Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, New Jersey 08854, USA.
Curr Opin Plant Biol. 2006 Apr;9(2):157-63. doi: 10.1016/j.pbi.2006.01.009. Epub 2006 Feb 3.
With a size approximating that of the human genome, the maize genome is about to become the largest plant genome yet sequenced. Contributing to that size are a whole-genome duplication event and a retrotransposition explosion that produced a large amount of repetitive DNA. This DNA is greatly under-represented in cDNA collections, so analysis of the maize transcriptome has been an expedient way of assessing the gene content of maize. Over 2 million maize cDNA sequences are now available, making maize the third most widely studied organism, behind mouse and man. To date, the sequencing of large-sized DNA clones has been largely driven by the genetic interests of different investigators. The recent construction of a physical map that is anchored to the genetic map will aid immensely in the maize genome-sequencing effort. However, studies showing that the repetitive DNA component is highly polymorphic among maize inbred lines point to the need to sample vertically a few specific regions of the genome to evaluate the extent and importance of this variability.
玉米基因组的大小与人类基因组相近，即将成为已测序的最大植物基因组。造成这种大小的原因是一次全基因组复制事件和一次逆转座爆发，产生了大量的重复DNA。这种DNA在cDNA文库中的代表性极低，因此对玉米转录组的分析一直是评估玉米基因含量的便捷方法。目前已有超过200万个玉米cDNA序列，使玉米成为研究最为广泛的第三种生物，仅次于小鼠和人类。迄今为止，大型DNA克隆的测序工作在很大程度上是由不同研究者的遗传学兴趣驱动的。最近构建的一张锚定在遗传图谱上的物理图谱将极大地助力玉米基因组测序工作。然而，有研究表明重复DNA成分在玉米自交系中高度多态，这表明需要对基因组的几个特定区域进行纵向取样，以评估这种变异性的程度和重要性。
