Differences in homologous recombination and maintenance of heteropolyploidy between Haloferax volcanii and Haloferax mediterranei.
Differences in homologous recombination and maintenance of heteropolyploidy between Haloferax volcanii and Haloferax mediterranei.
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DOI：
10.1093/g3journal/jkac306
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发表时间：
2023-04-11
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多倍性，即生物体中具有多于一个基因组拷贝的现象，在盐古菌中很常见。虽然为DNA修复提供了短期的好处，但多倍体通常被认为是一个“进化陷阱”，根据穆勒棘轮的概念，由于适应性的逐渐减少，物种将不可避免地衰退甚至灭绝。在大多数报道的古细菌多倍体的情况下，生物体的遗传状态被认为是同源性，即基因组的所有拷贝都是相同的。在这里，我们证明，虽然这确实是普遍的遗传状态嗜盐古菌Haloferax volcano ii，其近亲H。一旦引入第二个等位基因，地中海贫血在非选择性环境中保持延长的异倍性状态。此外，在H. mediiiagenei的同源重组率低，而在H. volcanii表明在后者的物种重组率高。我们建议H. volcanii逃脱穆勒的棘轮通过一个有效的染色体均衡基因转换机制促进高度活跃的同源重组，而H. Mediterranean必须通过一种不同的、尚待阐明的机制来避开棘轮。
Polyploidy, the phenomenon of having more than one copy of the genome in an organism, is common among haloarchaea. While providing short-term benefits for DNA repair, polyploidy is generally regarded as an “evolutionary trap” that by the notion of the Muller's ratchet will inevitably conclude in the species' decline or even extinction due to a gradual reduction in fitness. In most reported cases of polyploidy in archaea, the genetic state of the organism is considered as homoploidy i.e. all copies of the genome are identical. Here we demonstrate that while this is indeed the prevalent genetic status in the halophilic archaeon Haloferax volcanii, its close relative H. mediterranei maintains a prolonged heteroploidy state in a nonselective environment once a second allele is introduced. Moreover, a strong genetic linkage was observed between two distant loci in H. mediterranei indicating a low rate of homologous recombination while almost no such linkage was shown in H. volcanii indicating a high rate of recombination in the latter species. We suggest that H. volcanii escapes Muller's ratchet by means of an effective chromosome-equalizing gene-conversion mechanism facilitated by highly active homologous recombination, whereas H. mediterranei must elude the ratchet via a different, yet to be elucidated mechanism.
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影响因子：
14.9
作者：
Medlar AJ;Törönen P;Holm L
通讯作者：
Holm L
嗜盐古菌中受调控的多倍体。
影响因子：
3.7
作者：
Breuert S;Allers T;Spohn G;Soppa J
通讯作者：
Soppa J
影响因子：
4
作者：
Soltis, Pamela S.;Marchant, D. Blaine;Soltis, Douglas E.
通讯作者：
Soltis, Douglas E.
影响因子：
64.8
作者：
KONDRASHOV, AS
通讯作者：
KONDRASHOV, AS
代谢多功能嗜盐古菌 Haloferax mediterranei（一种聚（3-羟基丁酸酯-co-3-羟基戊酸酯）生产者）的完整基因组序列
影响因子：
3.2
作者：
Han, Jing;Zhang, Fan;Xiang, Hua
通讯作者：
Xiang, Hua