Barros Paula, Blanco Miguel G, Boán Francisco, Gómez-Márquez Jaime
Departamento de Bioquímica e Bioloxía Molecular, Facultade de Bioloxía-CIBUS, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Mol Phylogenet Evol. 2008 Nov;49(2):488-94. doi: 10.1016/j.ympev.2008.07.021. Epub 2008 Aug 6.
Minisatellites are tandem repeats of short DNA units widely distributed in genomes. However, the information on their dynamics in a phylogenetic context is very limited. Here we have studied the organization of the MsH43 locus in several species of primates and from these data we have reconstructed the evolutionary history of this complex minisatellite. Overall, with the exception of gibbon, MsH43 has an organization that is asymmetric, since the distribution of repeats is distinct between the 5' and 3' halves, and heterogeneous since there are many different repeats, some of them characteristic of each species. Inspection of the MsH43 arrays showed the existence of many duplications and deletions, suggesting the implication of slippage processes in the generation of polymorphism. Concerning the evolutionary history of this minisatellite, we propose that the birth of MsH43 may be situated before the divergence of Old World Monkeys since we found the existence of some MsH43 repeat motifs in prosimians and New World Monkeys. The analysis of MsH43 in apes revealed the existence of an evolutionary breakpoint in the pathway that originated African great apes and humans. Remarkably, human MsH43 is more homologous to orang-utan than to the corresponding sequence in gorilla and chimpanzee. This finding does not comply with the evolutionary paradigm that continuous alterations occur during the course of genome evolution. To adjust our results to the standard phylogeny of primates, we propose the existence of a wandering allele that was maintained almost unaltered during the period that extends between orang-utan and humans.
微卫星是短DNA单元的串联重复序列，广泛分布于基因组中。然而，关于它们在系统发育背景下的动态信息非常有限。在这里，我们研究了几种灵长类动物中MsH43位点的组织情况，并根据这些数据重建了这个复杂微卫星的进化历史。总体而言，除长臂猿外，MsH43的组织是不对称的，因为5'和3'半区的重复序列分布不同，而且是异质的，因为有许多不同的重复序列，其中一些是每个物种特有的。对MsH43阵列的检查显示存在许多重复和缺失，这表明滑动过程在多态性产生中起作用。关于这个微卫星的进化历史，我们提出MsH43的诞生可能早于旧世界猴的分化，因为我们在原猴和新世界猴中发现了一些MsH43重复基序。对猿类中MsH43的分析揭示了在起源于非洲大猿和人类的进化途径中存在一个进化断点。值得注意的是，人类MsH43与猩猩的同源性高于与大猩猩和黑猩猩相应序列的同源性。这一发现不符合基因组进化过程中持续发生变化的进化范式。为了使我们的结果与灵长类动物的标准系统发育相匹配，我们提出存在一个游荡等位基因，它在猩猩和人类之间的时期几乎保持不变。
