Kamm A, Galasso I, Schmidt T, Heslop-Harrison J S
Department of Cell Biology, John Innes Centre, Norwich, UK.
Plant Mol Biol. 1995 Mar;27(5):853-62. doi: 10.1007/BF00037014.
We have analysed a family of highly repetitive DNA from Arabidopsis arenosa (L.) Lawalrée [syn. Cardaminopsis arenosa (L.) Hayck] composed of AT-rich tandem repeats of 166-179 bp in head to tail organization. Sequence comparison between several repeat units revealed a high level of divergence of 4.5% to 25%. The sequence family shows more than 58% homology to satellite sequences described in Arabidopsis thaliana (L.) Heynh. but no homology to other satellite repeats in the Cruciferae. Within the genus Arabidopsis the satellite sequence was found to be present in A. thaliana and Arabidopsis suecica (Fries) Norrlin, but not in Arabidopsis griffithiana (Boiss.) N. Busch and Arabidopsis pumila (Stephan) N. Busch. In situ hybridization to metaphase chromosomes of A. arenosa (2n = 4x = 32) showed the sequence to be localized at the centromeres of all 32 chromosomes with substantial hybridization along the chromosome arms. Using Southern hybridization and in situ hybridization, we give evidence that A. suecica is a hybrid of A. thaliana and A. arenosa. A considerable reorganization of the A. thaliana satellite sequence pAL1 occurred in the hybrid genome while no molecular change of the A. arenosa repeat was observed in the hybrid. Analysis of related repeats enabled differentiation between closely related genomes and are useful for the investigation of hybrid genomes.
我们分析了沙生拟南芥（L.）Lawalrée [同物异名：岩生碎米荠（L.）Hayck] 的一个高度重复DNA家族，其由166 - 179 bp的富含AT的串联重复序列组成，呈头对头排列。几个重复单元之间的序列比较显示出4.5%至25%的高度差异。该序列家族与拟南芥（L.）Heynh.中描述的卫星序列具有超过58%的同源性，但与十字花科中的其他卫星重复序列无同源性。在拟南芥属内，发现该卫星序列存在于拟南芥和瑞典拟南芥（Fries）Norrlin中，但不存在于格里菲斯拟南芥（Boiss.）N. Busch和矮小拟南芥（Stephan）N. Busch中。对沙生拟南芥（2n = 4x = 32）中期染色体的原位杂交显示，该序列定位于所有32条染色体的着丝粒处，并且沿着染色体臂有大量杂交信号。通过Southern杂交和原位杂交，我们证明瑞典拟南芥是拟南芥和沙生拟南芥的杂交种。在杂交基因组中，拟南芥卫星序列pAL1发生了相当大的重组，而在杂交种中未观察到沙生拟南芥重复序列的分子变化。对相关重复序列的分析能够区分密切相关的基因组，并且对于杂交基因组的研究很有用。
