Nature Genetics：苹果基因组草图成功绘制

2010/08/31 10:43:20

导读：8月29日，一国际科研小组报道称他们绘出了广受人们喜爱的“金冠苹果”的基因组草图。这将有助于从基因水平上分析苹果性状，培育更多苹果新品种。

据新华社报道称，苹果基因组中含有7亿多个碱基对，其中有大段重复的基因。研究人员说，也许是大量的重复基因使苹果具有较多的染色体数目。与苹果同属蔷薇科的桃和草莓等水果的染色体数在7到9之间，而苹果的染色体数为17。

通过基因分析，研究人员还查明了苹果的“身世”。苹果与其他水果“亲戚”之间的进化分叉可能发生在五六千万年前，而这正是地球上发生大灾难的时候。这场大灾难导致恐龙灭绝。苹果的“祖先”植物可能是为了适应大灾难后的环境，逐步发生基因变化，最终进化成了今天的苹果树。

正是这些与其他水果不同的基因决定了苹果独特的风味和口感。此次绘出的苹果基因组草图，将有助于今后采用基因手段改良苹果，比如培育更脆、更多汁的苹果品种。

苹果是世界上最重要的水果之一。据介绍，现在全球每年苹果产量超过6000万吨。

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The genome of the domesticated apple (Malus × domestica Borkh.)

Nature Genetics doi:10.1038/ng.654

We report a high-quality draft genome sequence of the domesticated apple (Malus × domestica). We show that a relatively recent (>50 million years ago) genome-wide duplication (GWD) has resulted in the transition from nine ancestral chromosomes to 17 chromosomes in the Pyreae. Traces of older GWDs partly support the monophyly of the ancestral paleohexaploidy of eudicots. Phylogenetic reconstruction of Pyreae and the genus Malus, relative to major Rosaceae taxa, identified the progenitor of the cultivated apple as M. sieversii. Expansion of gene families reported to be involved in fruit development may explain formation of the pome, a Pyreae-specific false fruit that develops by proliferation of the basal part of the sepals, the receptacle. In apple, a subclade of MADS-box genes, normally involved in flower and fruit development, is expanded to include 15 members, as are other gene families involved in Rosaceae-specific metabolism, such as transport and assimilation of sorbitol.