Recombination rates between adjacent genic and retrotransposon regions in maize vary by 2 orders of magnitude
Recombination rates between adjacent genic and retrotransposon regions in maize vary by 2 orders of magnitude
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DOI：
10.1073/pnas.022635499
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发表时间：
2002-01-22
影响因子：
11.1
通讯作者：
Dooner, HK
中科院分区：
文献类型：
--
作者：
Fu, HH;Zheng, ZW;Dooner, HK
真核生物中的遗传图谱长度和基因数量的变化远小于基因组大小，这就产生了重组仅限于基因的假设。玉米复杂的基因组含有大部分重复DNA，主要由成簇排列的反转录转座子组成。在这里，我们直接评估逆转录转座子簇和基因对遗传长度的贡献。我们首先测量了青铜（bz）基因座两侧相邻纯合遗传间隔的重组。然后，我们分离和表征两个细菌人工染色体克隆含有这些间隔。在基因密集且缺乏反转录转座子的远端侧，比基因贫乏且含有大簇甲基化反转录转座子的近端侧，扩增几乎高2个数量级。我们的结论是，在玉米中的重复反转录转座子DNA，构成了基因组的大部分，最有可能的贡献很少，如果有的话，遗传长度。
Genetic map length and gene number in eukaryotes vary considerably less than genome size, giving rise to the hypothesis that recombination is restricted to genes. The complex genome of maize contains a large fraction of repetitive DNA, composed principally of retrotransposons arranged in clusters. Here, we assess directly the contribution of retrotransposon clusters and genes to genetic length. We first measured recombination across adjacent homozygous genetic intervals on either side of the bronze (bz) locus. We then isolated and characterized two bacterial artificial chromosome clones containing those intervals. Recombination was almost 2 orders of magnitude higher in the distal side, which is gene-dense and lacks retrotransposons, than in the proximal side, which is gene-poor and contains a large cluster of methylated retrotransposons. We conclude that the repetitive retrotransposon DNA in maize, which constitutes the bulk of the genome, most likely contributes little if any to genetic length.