García Graciela, Gutiérrez Verónica, Ríos Néstor
Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Montevideo, Uruguay.
Front Genet. 2022 Jun 20;13:903683. doi: 10.3389/fgene.2022.903683. eCollection 2022.
The term Annual killifish describes a short-lived and amazing group of vertebrates inhabiting temporary ponds exposed to an extremely variable environment during its short lifespan in South America and Africa, leading to the death of the entire adult population during the dry season. is a specious genus of the family Rivulidae, with ∼58 currently recognized species, extensively distributed in the temperate Neotropical region. Herein, we reviewed different aspects of the evolutionary biology with emphasis on the genome dynamic linked to the burst speciation process in this genus. constitutes an excellent model to study the genomic evolutionary processes underlying speciation events, since all the species of this genus analyzed so far share an unusually large genome size, with an average DNA content of 5.95 ± 0.45 picograms per diploid cell (mean C-value of about 2.98 pg). The drastic nuclear DNA-increasing would be associated with a considerable proportion of transposable elements (TEs) found in the genomes. The genomic proportion of the moderately repetitive DNA in the genome represents approximately twice (45%) the amount of the repetitive components of the highly related sympatric and syntopic rivulinae taxon (25%), as well as from other rivulids and actinopterygian fish. These events could explain the great genome instability, the high genetic diversity, chromosome variability, as well as the morphological diversity in species of . Thus, species of this genus represent new model systems linking different evolutionary processes: drastic genome increase, massive TEs genomic representation, high chromosome instability, occurrence of natural hybridization between sister species, and burst speciation events.
“一年生鳉鱼”一词描述了一类寿命短暂却令人称奇的脊椎动物，它们栖息于南美洲和非洲的临时性池塘中，在其短暂的生命周期里，所处环境极端多变，这导致整个成年种群在旱季死亡。[该属名未给出具体中文名称]是鳉科的一个似是而非的属，目前已识别出约58个物种，广泛分布于新热带区温带地区。在此，我们回顾了进化生物学的不同方面，重点关注与该属爆发式物种形成过程相关的基因组动态。[该属名未给出具体中文名称]构成了一个研究物种形成事件背后基因组进化过程的绝佳模型，因为到目前为止分析的该属所有物种都共享异常大的基因组大小，每个二倍体细胞的平均DNA含量为5.95±0.45皮克（平均C值约为2.98皮克）。核DNA的急剧增加与在[该属名未给出具体中文名称]基因组中发现的相当比例的转座元件（TEs）有关。[该属名未给出具体中文名称]基因组中中度重复DNA的基因组比例约为高度相关的同域和同地的鳉亚科分类群[该分类群名未给出具体中文名称]（25%）以及其他鳉科鱼类和辐鳍鱼类重复成分数量的两倍（45%）。这些事件可以解释[该属名未给出具体中文名称]物种中巨大的基因组不稳定性、高遗传多样性、染色体变异性以及形态多样性。因此，该属物种代表了连接不同进化过程的新模型系统：基因组急剧增加、大量TEs的基因组呈现、高染色体不稳定性、姐妹物种间自然杂交的发生以及爆发式物种形成事件。
