Somatic Mutations and Genome Stability Maintenance in Clonal Coral Colonies
Somatic Mutations and Genome Stability Maintenance in Clonal Coral Colonies
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DOI：
10.1093/molbev/msz270
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发表时间：
2020-03-01
影响因子：
10.7
通讯作者：
Palumbi, Stephen R.
中科院分区：
文献类型：
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作者：
Lopez, Elora H.;Palumbi, Stephen R.
多细胞生物面临的一个挑战是在长寿命内面对诱变剂时保持基因组的稳定性。不完善的基因组维护会导致体细胞中突变的积累，这与脊椎动物的肿瘤和衰老有关。殖民地造礁珊瑚通常很大，可以活几百年，很少出现可识别的肿瘤，被认为能将体细胞转化为配子产生者，因此它们是了解长期基因组维护的关键群体。为了测量体细胞突变的频率和模式，我们分析了四个风信子群体中每个群体的17到22个分支的转录本，确定了可能的单核苷酸变异，并用Sanger重新测序进行了验证。与人类皮肤癌不同，没有紫外线损伤引起的突变的特征，这表明要么修复效率高于脊椎动物，要么这些浅水热带动物具有强大的防晒保护作用。风信子的每个核苷酸的体细胞突变频率与非癌症的人类体细胞的突变频率相同(10(-7)个数量级)，并且随着年龄的增长，突变的积累是相似的。杂合性缺失变异的数量超过杂合性突变的获得，杂合性突变的数量接近2：1。虽然哺乳动物和珊瑚的突变频率相似，但杂合性缺失变化和潜在选择的优势可能会减少珊瑚等群体动物中有害突变的频率。这可能会限制体细胞突变对珊瑚生物体和潜在后代的有害影响。
One challenge for multicellular organisms is maintaining genome stability in the face of mutagens across long life spans. Imperfect genome maintenance leads to mutation accumulation in somatic cells, which is associated with tumors and senescence in vertebrates. Colonial reef-building corals are often large, can live for hundreds of years, rarely develop recognizable tumors, and are thought to convert somatic cells into gamete producers, so they are a pivotal group in which to understand long-term genome maintenance. To measure rates and patterns of somatic mutations, we analyzed transcriptomes from 17 to 22 branches from each of four Acropora hyacinthus colonies, determined putative single nucleotide variants, and verified them with Sanger resequencing. Unlike for human skin carcinomas, there is no signature of mutations caused by UV damage, indicating either higher efficiency of repair than in vertebrates, or strong sunscreen protection in these shallow water tropical animals. The somatic mutation frequency per nucleotide in A. hyacinthus is on the same order ofmagnitude (10(-7)) as noncancerous human somatic cells, and accumulation of mutations with age is similar. Loss of heterozygosity variants outnumber gain of heterozygosity mutations similar to 2:1. Although the mutation frequency is similar in mammals and corals, the preponderance of loss of heterozygosity changes and potential selection may reduce the frequency of deleteriousmutations in colonial animals like corals. This may limit the deleterious effects of somatic mutations on the coral organism as well as potential offspring.