Cytogenetic mapping of common bean chromosomes reveals a less compartmentalized small-genome plant species
Cytogenetic mapping of common bean chromosomes reveals a less compartmentalized small-genome plant species
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DOI：
10.1007/s10577-009-9031-4
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发表时间：
2009-04-01
影响因子：
2.6
通讯作者：
Schweizer, Dieter
中科院分区：
文献类型：
--
作者：
Pedrosa-Harand, Andrea;Kami, James;Schweizer, Dieter
利用BAC和其他几个基因组克隆的荧光原位杂交(FISH)技术，构建了菜豆3、4和7号染色体的细胞遗传学图谱。虽然所有克隆都是用遗传作图标记进行选择的，大多是单拷贝RFLP，但来自13个不同基因组区域的BAC的一大部分包含重复序列，这是根据多个FISH信号在染色体上的区域分布模式得出的结论：近着丝粒、亚端粒和分散。在所有11对染色体中均存在不同强度的近着丝粒重复序列，而在几个染色体末端存在亚端粒重复序列，但信号强度因BAC不同而不同，这表明该物种的末端异染色质部分可能由不同的重复序列组成。获得了23个无性系在三条染色体上的遗传距离和物理距离的相关性。这种相关性表明，在延伸的着丝粒周围区域，重组受到了抑制，这与之前报道的具有较大基因组的植物物种的情况类似。这些结果表明，相对较小的植物基因组也可能具有较大比例的重复序列，其中散布着除着丝粒周围异染色质外的其他区域的单拷贝序列，但在基因组的着丝粒周围部分表现出较低的重组。
Cytogenetic maps of common bean chromosomes 3, 4 and 7 were constructed by fluorescence in-situ hybridization (FISH) of BAC and a few other genomic clones. Although all clones were selected with genetically mapped markers, mostly with single-copy RFLPs, a large subset of BACs, from 13 different genomic regions, contained repetitive sequences, as concluded from the regional distribution patterns of multiple FISH signals on chromosomes: pericentromeric, subtelomeric and dispersed. Pericentromeric repeats were present in all 11 chromosome pairs with different intensities, whereas subtelomeric repeats were present in several chromosome ends, but with different signal intensities depending on the BAC, suggesting that the terminal heterochromatin fraction of this species may be composed of different repeats. The correlation of genetic and physical distances along the three studied chromosomes was obtained for 23 clones. This correlation suggests suppression of recombination around extended pericentromeric regions in a similar way to that previously reported for plant species with larger genomes. These results indicate that a relatively small plant genome may also possess a large proportion of repeats interspersed with single-copy sequences in regions other than the pericentromeric heterochromatin and, nevertheless, exhibit lower recombination around the pericentromeric fraction of the genome.