Genome Structure of Bdelloid Rotifers: Shaped by Asexuality or Desiccation?
Genome Structure of Bdelloid Rotifers: Shaped by Asexuality or Desiccation?
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DOI：
10.1093/jhered/esq008
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发表时间：
2010-03-01
影响因子：
3.1
通讯作者：
Arkhipova, Irina R.
中科院分区：
文献类型：
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作者：
Gladyshev, Eugene A.;Arkhipova, Irina R.
蛭形轮虫是一种微小的无脊椎动物，以其古老的无性繁殖和在任何生命阶段的干燥环境中生存的能力而闻名。预计这两个因素都将对它们的基因组结构产生深远的影响。最近的分子研究表明，虽然蛭形基因组的基因丰富的区域组织为共线性对的密切相关的序列和重复DNA耗尽，亚端粒区域窝藏不同的转座因子和水平获得的外源基因。尽管无性繁殖预期会导致有害转座子的耗尽，但似乎只有干燥才有能力产生所有未被发现的基因组特性。干燥诱导的DNA损伤的修复需要同源模板的存在，在基因丰富的区域保持共线对，并选择不插入可能导致染色体重排的重复DNA。干燥也可能诱导恢复动物的能力的暂时状态，使它们能够获得环境DNA。即使蛭形类动物进行罕见或模糊的有性生殖，所有这些特征仍然可能存在。通过分析全基因组序列和比较失去干燥生存能力的物种中外源基因和转座子的含量，可以澄清无性和干燥对基因组组织的相对贡献。
Bdelloid rotifers are microscopic invertebrate animals best known for their ancient asexuality and the ability to survive desiccation at any life stage. Both factors are expected to have a profound influence on their genome structure. Recent molecular studies demonstrated that, although the gene-rich regions of bdelloid genomes are organized as colinear pairs of closely related sequences and depleted in repetitive DNA, subtelomeric regions harbor diverse transposable elements and horizontally acquired genes of foreign origin. Although asexuality is expected to result in depletion of deleterious transposons, only desiccation appears to have the power to produce all the uncovered genomic peculiarities. Repair of desiccation-induced DNA damage would require the presence of a homologous template, maintaining colinear pairs in gene-rich regions and selecting against insertion of repetitive DNA that might cause chromosomal rearrangements. Desiccation may also induce a transient state of competence in recovering animals, allowing them to acquire environmental DNA. Even if bdelloids engage in rare or obscure forms of sexual reproduction, all these features could still be present. The relative contribution of asexuality and desiccation to genome organization may be clarified by analyzing whole-genome sequences and comparing foreign gene and transposon content in species which lost the ability to survive desiccation.