Heterochromatin and satellite DNA in man: properties and prospects.
Heterochromatin and satellite DNA in man: properties and prospects.
复制标题
人类异染色质和卫星 DNA：特性和前景。
DOI：
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发表时间：
1979
影响因子：
9.8
通讯作者：
B. John
中科院分区：
文献类型：
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作者：
G. Miklos;B. John
在回顾人类异染色质和卫星DNA的性质时，很明显，人类基因组不容易用于卫星DNA假定功能的实验测试。由于脊椎动物和无脊椎动物卫星DNA的已知结构特性的光谱是广泛重叠的，另一种方法是通过实验操作生物体的异染色质，然后评估结果的一般性。当在果蝇身上进行这一实验时，结果并不支持大多数关于卫星DNA功能的流行假说。果蝇是一种确实可以进行这种实验方法的生物。然而，它们确实揭示了对减数分裂系统的一个重要影响，即在已知富含卫星DNA的异染色质存在的情况下，交叉事件的位置可以显著改变。这种效应并不是果蝇独有的，因为从哺乳动物和蚱蜢的自然环境中都可以很容易地获得支持数据。在所有这样的情况下，当异色块在大小上很大，并且在位置上不居中时，效果最容易辨别，这不适用于MAN。然而，人类系统提供了其他潜力。自然产生的异染色质多态的普遍存在，加上人类基因组对扰动的极端敏感性，为评估卫星DNA数量变化可能产生的体细胞影响提供了一些空间。
In reviewing the properties of heterochromatin and satellite DNA in man, it is clear that the human genome does not readily lend itself to experimental tests of the postulated functions for satellite DNA. Since the spectrum of known structural properties of vertebrate and invertebrate satellite DNAs are broadly overlapping, an alternative avenue is to experimentally manipulate the heterochromatin of an organism, and then evaluate the generality of the results. When this is done in Drosophila melanogaster, the one organism where such an experimental approach is indeed possible, the results provide no support for most of the popular hypotheses concerning satellite DNA function. They do, however, reveal an important effect on the meiotic system, namely that the position of crossover events can be markedly altered in the presence of heterochromatin known to be rich in satellite DNAs. This effect is not peculiar to Drosophila, since supporting data are readily available from natural situations in both mammals and grasshoppers. In all such cases, the effects are most easily discernible where the heterochromatic blocks are substantial in size, and non-centric in location, situations which do not apply in man. The human system, however, offers other potentials. The ubiquity of naturally occurring heterochromatic polymorphisms, coupled with the extreme sensitivity of the human genome to perturbation, offers some scope for assessing the possible somatic effects of alterations in the amount of satellite DNA.