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Runaway GC Evolution in Gerbil Genomes.
Molecular Biology and Evolution ( IF 10.7 ) Pub Date : 2020-04-24 , DOI: 10.1093/molbev/msaa072 Rodrigo Pracana 1 , Adam D Hargreaves 1 , John F Mulley 2 , Peter W H Holland 1
Molecular Biology and Evolution ( IF 10.7 ) Pub Date : 2020-04-24 , DOI: 10.1093/molbev/msaa072 Rodrigo Pracana 1 , Adam D Hargreaves 1 , John F Mulley 2 , Peter W H Holland 1
Affiliation
Recombination increases the local GC-content in genomic regions through GC-biased gene conversion (gBGC). The recent discovery of a large genomic region with extreme GC-content in the fat sand rat Psammomys obesus provides a model to study the effects of gBGC on chromosome evolution. Here, we compare the GC-content and GC-to-AT substitution patterns across protein-coding genes of four gerbil species and two murine rodents (mouse and rat). We find that the known high-GC region is present in all the gerbils, and is characterized by high substitution rates for all mutational categories (AT-to-GC, GC-to-AT, and GC-conservative) both at synonymous and nonsynonymous sites. A higher AT-to-GC than GC-to-AT rate is consistent with the high GC-content. Additionally, we find more than 300 genes outside the known region with outlying values of AT-to-GC synonymous substitution rates in gerbils. Of these, over 30% are organized into at least 17 large clusters observable at the megabase-scale. The unusual GC-skewed substitution pattern suggests the evolution of genomic regions with very high recombination rates in the gerbil lineage, which can lead to a runaway increase in GC-content. Our results imply that rapid evolution of GC-content is possible in mammals, with gerbil species providing a powerful model to study the mechanisms of gBGC.
中文翻译:
沙鼠基因组中GC的失控进化。
重组通过偏向GC的基因转换(gBGC)增加了基因组区域的局部GC含量。最近发现肥胖沙鼠Psammomys obesus中具有极高GC含量的大基因组区域提供了一个模型来研究gBGC对染色体进化的影响。在这里,我们比较了四个沙鼠物种和两个鼠类啮齿动物(小鼠和大鼠)的跨蛋白质编码基因的GC含量和GC-to-AT替换模式。我们发现,已知的高GC区域存在于所有沙鼠中,其特征是所有突变类别(从AT到GC,从GC到AT和GC保守)的同义词和非同义词的高取代率网站。较高的GC含量与较高的GC含量相符,即较高的GC含量与AT / GC的速率一致。此外,我们在已知区域之外发现了300多个基因,这些值与沙鼠中AT-to-GC同义替换率的偏远值有关。其中,超过30%的组织成至少17个大型集群,可以在兆数据库规模上观察到。不寻常的GC偏斜取代模式表明,沙鼠谱系中具有很高重组率的基因组区域的进化,这可能导致GC含量的失控增加。我们的结果表明,哺乳动物中GC含量的快速进化是可能的,而沙鼠物种为研究gBGC的机理提供了强大的模型。
更新日期:2020-04-24
中文翻译:
沙鼠基因组中GC的失控进化。
重组通过偏向GC的基因转换(gBGC)增加了基因组区域的局部GC含量。最近发现肥胖沙鼠Psammomys obesus中具有极高GC含量的大基因组区域提供了一个模型来研究gBGC对染色体进化的影响。在这里,我们比较了四个沙鼠物种和两个鼠类啮齿动物(小鼠和大鼠)的跨蛋白质编码基因的GC含量和GC-to-AT替换模式。我们发现,已知的高GC区域存在于所有沙鼠中,其特征是所有突变类别(从AT到GC,从GC到AT和GC保守)的同义词和非同义词的高取代率网站。较高的GC含量与较高的GC含量相符,即较高的GC含量与AT / GC的速率一致。此外,我们在已知区域之外发现了300多个基因,这些值与沙鼠中AT-to-GC同义替换率的偏远值有关。其中,超过30%的组织成至少17个大型集群,可以在兆数据库规模上观察到。不寻常的GC偏斜取代模式表明,沙鼠谱系中具有很高重组率的基因组区域的进化,这可能导致GC含量的失控增加。我们的结果表明,哺乳动物中GC含量的快速进化是可能的,而沙鼠物种为研究gBGC的机理提供了强大的模型。