Nucleotide excision repair (NER) is the most versatile DNA repair pathway as it removes different kinds of bulky lesions. Due to its essential role for genome integrity, it has appeared early in the evolution of species. However, most published studies are focused on humans, mice, yeast or bacteria. Considering the large amount of information on genome databases, it is currently possible to retrieve sequences from NER components in many organisms. Therefore, we have characterized the potential orthologs of 10 critical components of the human NER pathway in 12 eukaryotic species by using similarity and structural criteria through the use of bioinformatics tools. This approach has allowed us to characterize gene and protein structures comparatively, taking a glance at some evolutionary aspects of the NER pathway. We have obtained significant search results for the majority of the proteins in most of the organisms studied, mainly for factors that play a pivotal role in the pathway. However, we have revisited significant differences and found new aspects that may imply a distinct functioning of this pathway in different organisms. Through the demonstration of the heterogeneity of the gene structures and a variety in the protein architecture of the NER components evaluated, our results show important differences between human NER and evolutionarily distant eukaryotes. We highlight the lack of a canonical XPD in chicken, the divergence of XPA in plants and protozoans and the absence of XPE in the invertebrate species analyzed. In spite of this, it is remarkable the presence of this excision repair mechanism in a high number of evolutionary distant organisms, being present since the origin of eukaryotes.

核苷酸切除修复（NER）是最通用的DNA修复途径，因为它可以去除各种体积较大的病变。由于其对于基因组完整性的重要作用，它已经出现在物种进化的早期。但是，大多数已发表的研究集中在人类，小鼠，酵母或细菌上。考虑到基因组数据库上的大量信息，目前有可能从许多生物的NER成分中检索序列。因此，我们已经通过使用生物信息学工具使用相似性和结构标准来表征了12个真核生物物种中人类NER途径的10个关键组成部分的潜在直系同源物。这种方法使我们能够比较表征基因和蛋白质的结构，对NER途径的某些进化方面一目了然。对于大多数研究的生物中的大多数蛋白质，我们已经获得了重要的搜索结果，主要是寻找在该途径中起关键作用的因子。但是，我们重新审视了重大差异并发现了可能暗示该途径在不同生物体中具有独特功能的新方面。通过证明基因结构的异质性以及所评估的NER成分的蛋白质结构的多样性，我们的结果表明了人类NER与进化距离较远的真核生物之间的重要差异。我们强调了鸡中缺乏规范的XPD，植物和原生动物中XPA的差异以及所分析的无脊椎动物物种中XPE的缺乏。尽管如此，在许多进化的远距离生物中仍然存在这种切除修复机制，