Homoplasy for size at microsatellite loci in humans and chimpanzees
Homoplasy for size at microsatellite loci in humans and chimpanzees
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DOI：
10.1101/gr.6.3.211
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发表时间：
1996-03-01
期刊：
影响因子：
7
通讯作者：
Freimer, NB
中科院分区：
文献类型：
--
作者：
Garza, JC;Freimer, NB
通过对两个复合微卫星的多个等位基因和黑猩猩和人类另外两个复合座位上相同大小的等位基因的单拷贝进行测序，检验了微卫星座位的同质性(不同等位基因大小的趋同)。在对多个等位基因进行测序的两个基因座中的一个上，发现了物种内和物种之间大小的广泛同质性。在两个物种中检测到相同大小等位基因的三个基因座上，测序显示了不同的内部结构。这些结果证实了理论上的预测，即微卫星座位上的特定部分突变应该产生大小相同但有许多突变不同的等位基因。序列数据揭示了微卫星以前未被识别的一类变异，并开辟了DNA测序可能允许从这些基因座提取更多信息的可能性，从而增加了它们作为遗传图谱研究的可变标记的能力。相反，这些数据还表明，在某些情况下，在几种分析方法中隐含的相同大小的等位基因在序列中相同的假设被违反。因此，在系统发育和其他研究中使用微卫星时应谨慎行事，在这些研究中，被检查的个体与共同祖先相隔了大量世代。
Homoplasy (convergence in the size of different alleles) at microsatellite loci was examined by sequencing multiple alleles of two compound microsatellites and single copies of alleles of the same size at two other compound loci in both chimpanzees and humans. At one of the two loci for which multiple alleles were sequenced, extensive homoplasy For size was uncovered both within and between species. At the three loci for which alleles of the same size were examined in the two species, sequencing demonstrated different internal structures. These results confirm theoretical predictions that a certain fraction of mutations at microsatellite loci should produce alleles that are identical in size but differ by a number of mutations. The sequence data reveal a previously unrecognized class of variation at microsatellites and open up the possibility that DNA sequencing may allow the extraction of more information from these loci, thus increasing their power as variable markers for genetic mapping studies. Conversely, the data also indicate that the assumption that alleles of the same size are identical in sequence, which is implicit in several methods of analysis, is violated in some cases. Therefore, caution should be used when employing microsatellites in phylogenetic and other studies in which the individuals being examined are separated by a great number of generations from a common ancestor.