Genomic distribution of heterochromatic sequences in equids: implications to rapid chromosomal evolution.
Genomic distribution of heterochromatic sequences in equids: implications to rapid chromosomal evolution.
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DOI：
10.1093/oxfordjournals.jhered.a111106
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发表时间：
1991-09
期刊：
影响因子：
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通讯作者：
H. Wichman;C. Payne;Oliver A. Ryder;Meredith J. Hamilton;M. Maltbie;Robert J. Baker
中科院分区：
文献类型：
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作者：
H. Wichman;C. Payne;Oliver A. Ryder;Meredith J. Hamilton;M. Maltbie;Robert J. Baker
我们描述了一个染色体快速进化的分子模型，该模型提出将重复DNA序列作为驱动力。这个模型的一个预测是，当异染色质促进了常染色质的广泛重排时，基因组的特征将是随机重复的序列，这些序列通过基因组内的运动活跃地改变了染色体的领域。或者，有人提出，在保守的染色体谱系中，每一类重复序列将被限制在特定的染色体区域。为了提供基线数据来检验这一模型，我们研究了六种马的四类重复元素。通过狭缝杂交分析这些序列在物种中的分布，以及Southern杂交表明这些序列的限制性内切点变异，证明这些序列处于进化的动态状态，原位杂交证明这些序列在非同源染色体和染色体区域之间广泛的基因组内移动。这些数据被解释为与该模型的预测相一致。尽管这显然不是驱动染色体进化的唯一分子因素，但该模型似乎是可行的，可以解释某些染色体进化模式，如核型巨型进化和某些类型的核型正射选择。
We describe a molecular model for rapid chromosomal evolution that proposes tandemly repeated DNA sequences as a driving force. A prediction of this model is that when extensive rearrangements of euchromatin have been facilitated by heterochromatin, genomes will be characterized by tandemly repeated sequences that have actively changed chromosomal fields by intragenomic movement. Alternatively, it is proposed that in conservative chromosomal lineage each class of tandemly repeated sequences will be restricted to a specific chromosomal field. To provide baseline data to test this model we examined four classes of tandemly repeated elements in six species of equids (Equus). Distribution of these sequences among species, as determined from slot blot analysis, and restriction site variation, shown by Southern blot hybridization, document that these sequences are in an evolutionarily dynamic state, and in situ hybridization documents extensive intragenomic movement among nonhomologous chromosomes and chromosomal fields. These data are interpreted as being compatible with the predictions of this model. Although this is clearly not the sole molecular factor driving chromosomal evolution, the model appears to be viable as an explanation of certain patterns of chromosomal evolution such as karyotypic megaevolution and some types of karyotypic orthoselection.